The Spirit Level Delusion

Welcome

2012-01-01T02:53:00.001Z

This website exists as a forum for additional notes and discussion related to the book The Spirit Level Delusion. Some of this information takes the form of extended footnotes, which can be accessed at the right-hand side of this page.

The meat of the argument is, of course, in the book itself—which is available here (UK), here (USA) and here (Sweden). If you haven't read it, my articles in the Wall Street Journal and Spiked Review of Books give a brief overview.

Please scroll down for more recent entries, including a fact-checking of the response given by The Spirit Level's authors to my 20 Questions, a rebuttal to their article in Prospect magazine and some highlights from Kate Pickett's interview on BBC Radio 4's More or Less.

You can also read (for free) the new chapter included in the second edition of the book, which deals with Wilkinson and Pickett's response to criticism. Download as PDF.

"This year’s most important publication"
— James Delingpole, The Telegraph

"If you haven’t read a book that made you laugh out loud on the bus or the Tube in a while, try Christopher Snowdon’s superb release, The Spirit Level Delusion. But the book’s subtle humour is not the reason I am recommending it. The Spirit Level Delusion is, above all, a book that delivers and goes well beyond the promise of its subtitle – 'fact-checking the left’s new theory of everything'... It may well be that the next big battle for a free society will be fought against the new anti-wealth egalitarianism. Christopher Snowdon has provided defenders of freedom with powerful ammunition."
— Kristian Niemietz, Institute of Economic Affairs

"Snowdon picks so many holes in the theory that were it a building it wouldn’t be passed as structurally sound by the most crooked of third world local government surveyors... Next time someone starts spouting off about “equality” – a goal that has dug more graves than all the gods in history combined – send them a copy of Snowdon’s excellent book and make sure they read it from cover to cover."

— Ed West, The Telegraph

"The Spirit Level Delusion not only successfully and dramatically undermines much of the evidence in The Spirit Level, but also takes on the other fashionable opponents of economic growth... His engaging discussion unpicks the evidence of the anti-growth brigade and demonstrates that it is selective and partial. This book is excellent “tube reading”.

— Philip Booth, City AM

"Comprehensive in its demolition...well written, amusingly thorough and easy to digest...You need this book."

— An Englishman's Castle

See also: Institute of Public Affairs Review and The Scotsman.

Inequality and anxiety

2011-12-21T15:11:00.002Z

Richard Smith has written an interesting article in Educational Theory which looks at the causal mechanism Wilkinson and Pickett propose in chapter 3 of The Spirit Level to explain the correlations they show in the rest of the book. As Smith writes...

The argument runs as follows. Unequal income leads to unequal status, and in a world where people are alert to and anxious about where they are positioned on the social ladder, this anxiety affects both mental and physical health. Psychological insecurity and distress rise; self-esteem falls.

There is, however, a problem tallying this theory with the empirical evidence.

A highly inconvenient fact for their thesis, and one that they fully acknowledge, is that over the time-scale under consideration self-esteem as well as anxiety ‘‘showed a very clear long-term upward trend. It looked as if, despite the rising anxiety levels, people were also taking a more positive view of themselves over time’’ (SL, 36). Surely, it would seem, anxiety about status should be reﬂected in lower, not higher, self-esteem.

Wilkinson and Pickett’s solution is to distinguish ‘‘healthy’’ self-esteem from the defensive kind found in those prone to violence, racism, and insensitivity to others. This latter kind is fragile and more akin to ‘‘whistling in the dark’’ (SL, 37); we might compare this analysis with Ruth Cigman’s discussion of ‘psychological fraudsters.’’

In the context this looks like a rather desperate strategy on Wilkinson and Pickett’s part to save the explanation in terms of concern for status and self-esteem.

I agree with Smith's analysis, but I think there is more to be said. Chapter 3 is crucial to everything that follows in The Spirit Level, but, despite being superficially plausible if read casually, what little evidence they present does not support their argument. Indeed, the evidence goes some way to refuting it.

They start the chapter with two graphs showing the rise in anxiety amongst US college students between 1952 and 1993 (based on research by June M. Twenge) (p. 34). These are the only graphs in the chapter and they show anxiety rising continuously since the early 1950s. Whatever else might have been responsible for this trend, it was not income inequality, as Wilkinson and Pickett acknowledge:

We are not suggesting that [these rises in anxiety] were triggered by increased inequality ... the rises in anxiety and depression seem to start well before the increases in inequality which in many countries took place during the last quarter of the twentieth century. (p. 35)

Not only did inequality not rise until much later, but inequality actually fell in the first half of the period. What bearing do these graphs have on their inequality hypothesis? It is not at all clear, but Wilkinson and Pickett promise to explain, saying: "It is important to understand what these rises in anxiety about before their relevance to inequality becomes clear."

Their explanation begins with the discussion moving from anxiety to self-esteem (p. 36). Self-esteem appears to have risen over the period in much the same way as anxiety, but this anxiety, as Smith says, seems incongruous with rising self-esteem. Wilkinson and Pickett square this circle by arguing that this is really quasi-self-esteem, which reflects the way school-children are taught to have excessive faith in themselves, leading to narcissism. There is, they say, good self-esteem and bad self-esteem, and this is the latter.

Smith has doubts about this argument, but even if we take it at face value, the connection with inequality eludes us. Neither anxiety nor self-reported self-esteem are in any way correlated with changes in the Gini coefficient.

Wilkinson and Pickett then introduce some causes of psychological stress which include "low social status, lack of friends, and stress in early life." They offer some rather banal observations such as "friends make you feel appreciated" and "how people see you matters." (p. 39) This is all perfectly plausible, but so what? Do people have fewer friends in less equal societies? We are not told, but there is no particular reason to think so.

The next study Wilkinson and Pickett discuss leaves us none the wiser because that, too, does not address income inequality at all (p. 41). They then return to the issue of anxiety and seem to be on the brink of explaining its relevance to inequality.

Why have these social anxieties increased so dramatically over the last half century—as Twenge's studies showing rising levels of anxiety and fragile, narcissistic egos suggest they have? Why does the social evaluative threat seem so great? A plausible explanation is the break-up of the settled communities of the past. (p. 42)

Again, this is more than plausible. The rapid rise in geographical mobility over the last half-century may well offer part of the explanation for the decline in social cohesion that has been documented by Putman and others. People who leave home are less likely to benefit from being around old friends and family. "Familiar faces," they write, "have been replaced by a constant flux of strangers. As a result, who we are, identify with, is endlessly open to question."(p. 42)

A lot of this appeals to common sense and is often based on sound sociological evidence, but still the link with income inequality is nowhere to be seen. It only arrives in the final pages of the chapter, and even then, speculatively. They repeat their admission that there is no correlation between rates of anxiety and rates of inequality...

Although the rises in anxiety that seem to centre on social evaluation pre-date the rise in anxiety...

But they make the association all the same...

...it is not difficult to see how rising inequality and social status differences may impact on them. (p. 43)

This is no more than a hunch and no evidence is presented in its favour. In fact, is is difficult to see how inequality impacts upon "the rise in anxiety", because none of the variables they associate with anxiety seem to be linked with inequality, and "the rise in anxiety" itself is demonstrably not linked with inequality in the time-series graphs that kicked off the chapter. Nothing they say in the intervening pages explains why anxiety rose when inequality was falling and continued to rise (at the same rate) when inequality went up.

Further hunches follow:

Greater inequality seems to heighten people's social evaluation anxieties by increasing the importance of social status. (p. 43)

No evidence is presented for this assertion (the only references given are a quote from a nineteenth century philosopher and a study which shows that people are judged on first impressions—neither mentions inequality).

Greater inequality is likely to be accompanied by increased status competition. It is not simply that where the stakes are higher each of us worries more about where he or she comes. It is also that we are likely to pay more attention to social status in how we assess each other. (p. 44) (my italics)

They may believe so, but what they think "likely" can only be viewed as conjecture unless it is backed up with evidence. This, they fail to provide. Instead, they discuss the "stark contrast between the way people see and present themselves" in Japan and the USA. The Japanese, we are told, are more modest while Americans are "more likely to attribute individual successes to their own abilities." This leads Wilkinson and Pickett to jump to the heroic conclusion that:

As greater inequality increases status competition and social evaluative threat, egos have to be propped up by self-promoting and self-enhancing strategies.

... Not only do large inequalities produce all the problems associated with social differences and the divisive class prejudices which go with them, but, as later chapters show, it also weakens community life, reduces trust, and increases violence. (p. 45)

If the comparison between Japan and the USA is supposed to seal the deal with the reader, it falls flat. As Saunders and others have noted, it would be hard to find a more hierarchical and status-conscious society than Japan. The modesty Wilkinson and Pickett attribute to the Japanese applies to many Asian societies. Furthermore, Japan's high suicide rate is not indicative of a low-anxiety nation.

By contrasting Japan and America, Wilkinson and Pickett are comparing apples with oranges. They are very different countries, to be sure, but the difference is rooted in culture, not income inequality. Wilkinson and Pickett say that by focusing on these two countries, they can contrast "the most equal with almost the most unequal of the rich market democracies". "Almost" is the key word here. The most unequal country in their book is actually Singapore, but if they had compared Singapore with Japan, they would not have achieved the desired effect.

So, to recap, Wilkinson and Pickett's theory goes as follows: Those of us who live in rich societies are "much more anxious than we used to be" (p. 33) and this rise in anxiety has been mirrored by a rise in self-esteem. This self-esteem, however, is not real self-esteem but narcissism driven by stress. This stress is driven by feelings of inferiority and the "social evaluative threat" which are "likely" to be driven by inequality.

There are many problems with this torturous chain of reasoning, not least Wilkinson and Pickett's tendency to oversimplify complex ideas and treat contentious theories as fact, but leaving them aside, let us take the proposition that stress and anxiety are the root causes of many modern social and health problems. If inequality is, in turn, the root cause of this anxiety, there must be a correlation between inequality and anxiety over time, but no amount of sophistry can disguise the fact that no such relationship exists.

Chapter 3 involves so many digressions and non-sequiturs that the unwary reader can be forgiven for having forgotten this little fact by the time they reach the end, and yet those two graphs indicating no correlation between anxiety and inequality seriously undermine their hypothesis.

But those graphs tell us something more. Wilkinson and Pickett are forced to accept that the rise in anxiety between 1950 and 1980 cannot be blamed on inequality because inequality was flat or falling during this period, but they never ask the obvious question—if inequality was not the cause, what was?

If the anxiety data is to be believed—and Wilkinson and Pickett cast no doubt on it—something important clearly happened after 1952 (at the latest) which led to greater anxiety, but Wilkinson and Pickett display not a hint of curiosity as to what this might be. Had they not been so committed to their a priori hypothesis, they might have paid more attention to this mysterious third variable. As it is, they ignore it for the remainder of the book in favour of their hunch that inequality is somehow the culprit despite their own evidence.

Wilkinson in The Guardian

2011-12-04T15:27:00.002Z

Last week, Richard Wilkinson wrote an article for The Guardian in which he claimed that a large reduction in inequality took place in the 1930s which led to a large rise in life expectancy, despite economic hardship.

Rather surprisingly, health – and probably other indicators of wellbeing – continued to improve in the great depression of the 1930s. This is likely to have been partly because that period saw the most rapid sustained increase in equality on record.

There are two problems with this assertion. The first is that the Great Depression of the 1930s did not see "the most sustained increase inequality on record." The big fall in inequality began in 1939-40 as a result of the Second World War and continued through the austerity years of the 1940s. Rationing, conscription and full employment are the most plausible explanations for this decline.

As the graph below shows, this was an international phenomenon known as the Great Compression. A similar graph appears in the revised edition of The Spirit Level (p. 296) clearly showing little change in British inequality in the 1930s. (Both graphs show the share of income held by the top 1% of earners. Other measures tell the same story.) It is puzzling that Wilkinson, whose bachelor's degree was in economic history, can confuse the Great Depression with the Great Compression.

The second problem is that Wilkinson's only piece of empirical evidence linking reduced inequality with better health during this period comes from life expectancy data (he offers no evidence at all to support his hunch that "probably other indicators of wellbeing" also improved). Life expectancy is indeed a good proxy for health, but there was nothing remarkable about the improvements seen in the 1930s. As the graph below shows, life expectancy increased throughout the century at a steady rate. There is no historical correlation between inequality and health (nor with any of the other criteria studied in The Spirit Level).

Life expectancy neither rose more sharply when inequality was low, nor declined when inequality was high. Because of the sustained rise in life expectancy, it is possible to point to any event in the 20th century (except for the two world wars) and say that it coincided with a rise in life expectancy. It would be fatuous, but it would be factually correct. But if you were to say that x caused a rise in life expectancy—as Wilkinson is doing here—you would rightly be accused of mistaking correlation for causation and committing a basic a post hoc ergo propter hoc error.

Wilkinson is so committed to the theory that inequality is the main driver of social outcomes that he is compelled to view any period of history which saw a decline in inequality as a time of national revival, regardless of what the history books might say. In The Spirit Level, he and Pickett display nostalgia for wartime Britain, austerity Britain and the 1970s, despite these being notoriously miserable times to be alive. It is appropriate that the grim 1930s be added to that list.

The main aim of Wilkinson's article is to dismiss the academic field of happiness studies. More of that in January when the Institute of Economic Affairs publishes a monograph on that subject...

The Spirit Level Delusion: Chapter 10

2011-06-08T02:44:00.000+01:00

Hello there.

If you've reached this website by following the link to extra footnotes given in The Spirit Level Delusion, then welcome, and thank you for reading the book. You'll find the footnotes listed on the right-hand side of this page.

As an addendum to The Spirit Level Delusion I have also written an additional chapter discussing Wilkinson and Pickett's response to the criticisms The Spirit Level has received since it was published. As a courtesy to readers, this is available here as a free download (PDF).

This site isn't updated very often but there are a few other articles tucked away if you're suitably interested. If you haven't read the book yet, there are links to Amazon in the side-bar.

Thanks,

CJS

Does the Better Life Index support The Spirit Level?

2011-05-25T15:29:00.001+01:00

Yesterday, the Organisation for Economic Co-operation and Development (OECD) published the Better Life Index. This project aims to measure the quality-of-life in countries using eleven criteria.

Since it was founded in 1961, the OECD has helped governments design better policies for better lives for their citizens. More recently, the OECD has been keenly involved in the debate on measuring well-being. Based on this experience, these 11 topics reflect what the OECD has identified as essential to well-being in terms of material living conditions (housing, income, jobs) and quality of life (community, education, environment, governance, health, life satisfaction, safety and work-life balance).

Having gone to all this trouble to create a reliable index of well-being, it's worth asking whether the OECD data supports The Spirit Level's hypothesis that "more equal societies almost always do better"?

No, it doesn't. The poorest country—Portugal—does worst, but the data points appear to be scattered randomly.

In fact, if we drill down into the data we can see that not only is well-being not better in "more equal" countries, but the OECD's figures do not support The Spirit Level's key argument—that "more equal" countries have stronger social support networks which lead to a healthier and happier population.

Quality of social support network:

Life expectancy:

Self-reported health:

Life satisfaction:

There is no association between inequality and any of these variables. Indeed, with the exception of self-reported health—which seems to show the opposite of what The Spirit Level says—the regression lines are about as straight as you could expect from a randomly assorted set of data.

Taken together, the OECD's Better Life Index appears to support the view of a previous effort by The Economist to devise a quality-of-life index, which concluded:

There is no evidence for an explanation sometimes proffered for the apparent paradox of increasing incomes and stagnant life-satisfaction scores: the idea that an increase in someone’s income causes envy and reduces the welfare and satisfaction of others. In our estimates, the level of income inequality had no impact on levels of life satisfaction. Life satisfaction is primarily determined by absolute, rather than relative, status (related to states of mind and aspirations).

(Note on data: The first graph shows an index of all the OECD's criteria with each given equal weight. Singapore and Hong Kong are not OECD members so they do not feature in the list. Their absence can only benefit The Spirit Level's case here because these unequal countries tend to perform well under most criteria. As per The Spirit Level, tax havens and countries without equality data are excluded. All other counties with wealth greater than Portugal are included. The OECD produces well-respected inequality figures but these are not used in The Spirit Level (perhaps because they show Japan to be quite unequal). I have used The Spirit Level's preferred inequality figures here and throughout The Spirit Level Delusion.)

20 questions for Richard Wilkinson & Kate Pickett

2011-02-01T19:30:00.001Z

[Wilkinson and Pickett (W & P) have now responded to these questions. This post has been updated to show their answers, with my replies below. These are a set of straight-forward questions on simple points of fact that were raised on this blog in April 2010. Some websites have portrayed W & P's replies as being a response to the evidence and arguments in the book The Spirit Level Delusion. They're not. They have never responded to those, but their replies here are of interest all the same.]

1. Why do you exclude the Czech Republic, South Korea and Hong Kong from your analysis when all these societies are wealthier than Portugal?

Wilkinson & Pickett: There are different ways of measuring average income in different countries; the choice of measure makes small differences in precise ranking of countries by wealth. We chose countries ordered according to the Atlas Method, because this is used by the World Bank to classify countries into Low, Medium and High Income categories. Our source is the World Development Indicators Database, World Bank, April 2004*. From this list we selected the 50 richest countries, excluded those with populations less than 3 million and those without income inequality data from the United Nations. Our aim was to examine the impact of inequality on health and social problems among rich countries, where average levels of income are not related to health, happiness or well-being. Our selection criteria also mean that we only consider the older, rich, developed, market economies, and so allows us to compare like with like. The countries which our critics suggest we should fail to meet the criteria.

This is a key question and unfortunately W & P only reiterate what they said in the Appendix of The Spirit Level. I have never challenged their assertion that only wealthy Western industrialised nations should be included in the analysis. The question is which countries are "rich". Any cut-off point will be open to debate, but picking the top 50 for no other reason than that it is a round number is unnecessarily arbitrary.

W & P say that they selected the countries by picking those which appeared "on the ﬂat part of the curve at the top right in Figure 1.1 on p. 7, where life expectancy is no longer related to differences in Gross National Income" (The Spirit Level, p. 280). This is simply not true. The image below is a close up of the countries in Figure 1.1. Hungary, the Czech Republic, Slovenia and South Korea (Hong Kong is not shown) are all on "the flat part" and are all shown as being richer than Portugal and yet they are not included.

All I do in The Spirit Level Delusion is include countries of similar or greater wealth that should—by W & P's own criteria—have been included in the first place. I have not added poorer countries in, rather I have included rich developed societies that W & P excluded without good reason.

The World Bank gives figures for the Atlas method (in US dollars) and Purchasing Power Parity (in international dollars). The latter is more appropriate for international comparisons—the whole point of international dollars is to facilitate international comparisons. Even using W & P's arbitrary top 50 cut-off point, the World Bank's figures for 2005 show:

(9) Hong Kong: $34,900
(45) Slovenia: $22,140
(46) South Korea: $22,010
(48) Portugal: $22,070
(50) Czech Republic: $19,560

And the figures for 2008 show:

(16) Hong Kong: $43,960
(44) South Korea: $28,120
(46) Slovenia: $26,910
(55) Czech Republic: $22,790
(59) Portugal: $22,080

Whichever data set is used, there is no justification for including relatively poor countries like Greece and Portugal while excluding several nations which are manifestly comparable.

If we wish to "compare like with like", it is particularly important to include Asian countries other than Japan, because they demonstrate that the supposed benefits of Japanese equality are actually the result of social and cultural factors unique to Asian societies. Although very unequal, Hong Kong and Singapore perform well under almost every criteria although the W & P hypothesis predicts that they should perform worst. This reveals a puzzling lack of a dose-response relationship.

[*Although published in 2004, the figures refer to 2002 - CJS]

2. Why do you exclude Singapore from your graph of mental illness when you included it in the same graph when it was published in Olivers James' Affluenza?

Wilkinson & Pickett: Comparing the prevalence of mental illness in different societies has long been thought to be problematic because of cultural differences in labelling mental illness or in help-seeking behaviours. To overcome these limitations, the World Health Organization established a consortium to provide international comparisons of the prevalence of mental illness. As referenced in The Spirit Level, we use these WHO estimates for Belgium, France, Germany, Italy, the Netherlands, Spain and the USA. We added in estimates from Canada, the UK and Australia because they used almost exactly comparable methods (diagnostic interviews of random samples of the population) to the WHO studies. We did not include a survey of mental illness from Singapore in either of our peer-reviewed publications on this topic, or in The Spirit Level, because the WHO surveys included questions on illegal drug abuse and, in 1988, the death sentence became mandatory in Singapore for manufacturing, importing, exporting or trafficking drugs in small quantities. Possession of small quantities was taken as prima facie evidence of trafficking. We therefore consider that self-reported estimates of mental illness in Singapore survey will be under-estimates. However, even if Singapore is included, there is still a statistically significant association between income inequality and mental illness (r=0.58, p=0.04).

This doesn't answer the question of why they included Singapore in the graph they created for Affluenza and The Selfish Capitalist. Drugs are illegal in all the countries studied in their graph and admitting to having used a substance in a confidential mental health questionnaire is not grounds for prosecution for possession, regardless of the severity of the punishment.

Rates of anxiety and mood disorders found in the Singapore study indicate that the position of Singapore in the Affluenza graph is about right (ie. about the same as France).

We will come back to the reliability of their mental illness graph in question 14.

3. Why do you say that the USA’s decline in homicide ended in 2005 when 2008 saw the lowest number of homicides since 1965? As you must know, America's murder rate has halved in the last two decades despite rising inequality.

Wilkinson & Pickett: We started writing The Spirit Level in January 2007 and delivered it to our publisher in February 2008, so clearly we could not have accessed homicide data from 2008 – typically official statistics are published 2-3 years post-collection. At time of writing (mid-2010), the most up-to-date data are for 2008.

The homicide rate in the USA has indeed declined, on average over the past two decades, whilst income inequality has been rising. But, as we discuss in The Spirit Level, and show here, there is a match over time between bottom-sensitive measures of income inequality and changes in homicide rates.

The Spirit Level contains references to several articles published after February 2008, but we shall let that pass. On this occasion, I accept that my criticism was too hasty. I accept that W & P would not have had the homicide data for 2008 before The Spirit Level was published in hardback. Presumably they will correct their claim that the murder rate started to rise again in 2005 in the future editions?*

The substantive point remains, however. America's murder rate is at its lowest level since 1965 and it was very premature for W & P to suggest that the 2005-06 blip represented the start of an upward trend. This seems a small point but it important to their overall argument. The reason W & P are so keen to claim that the murder rate began rising in the 2000s is that the huge decline in American homicide coincided with growing equality. The sharp but inconvenient decline in the murder rate (and of crime generally) from the early 1990s does not sit easily with their theory that inequality is the root cause of homicide. As shown in The Spirit Level Delusion and elsewhere, W & P's evidence for linking the two is extremely tenuous.

* (UPDATE 2011: The second edition has appeared and they have not.)

4. Why did you use older data for your life expectancy/inequality graph than you used elsewhere in The Spirit Level? Is it because more recent data show no correlation with inequality?

Wilkinson & Pickett: To avoid the effects of random fluctuations in inequality measures in each country, we took the average of inequality measures published in four consecutive years of the UN Human Development Report. We then matched outcome data (including life expectancy) as nearly as possible to the same time frame as the measures of inequality. When looking at life expectancy against National Income per head we again took the most up to date measures of those covering the same time frame. There are also many recent studies that demonstrate a relationship between income inequality and health, see for example the study of more than 60 million individuals by Kondo and colleagues.

This simply doesn't make any sense. W & P's national income data come from 2002, therefore it is logical to use life expectancy data from 2002. Instead they use data from 2004 (as published in the UN Human Development Report (UN HDR) 2006).

But when they look at inequality, they use life expectancy figures from 2002 (as published in the UN HDR 2004), even though their inequality figures are averaged out from several different years. A better explanation is that the older edition of the report was preferred because it provided slightly better evidence of a correlation between inequality and longevity, albeit only when W & P's selection of countries were used.

I am by no means the first person to have spotted Richard Wilkinson's tendency to be choosy about which sets of data he uses to make his case:

"He [Wilkinson] gives no satisfactory explanation about why "the poorest 70%" should be chosen, and the suspicion must be that the choise is derived from the data."

Ken Judge, 'Income distribution and life expectancy: a critical appraisal', British Medical Journal, 1995

"The strength of association between absolute income and life expectancy seems quite sensitive to which countries are included. What constitutes an appropriate set of countries of this sort is certainly open to debate. Nevertheless, we have shown that compared with Wilkinson's selection of 23 countries, the addition of the other 10 equally wealthy nations that constitute the full sample, significantly changes the results."

J. Lynch, P. Due, C. Muntaner & G. Davey Smith, 'Social capital - Is it a good investment strategy for public health?', Journal of Epidemiological and Community Health, 2000

"Although many aspects of this debate are still unresolved, it has recently become clear that the findings of that paper [Wilkinson, BMJ, 1992] were an artifact of the selection of countries... the evidence for a correlation between income inequality and the health of the population is slowly dissipating’

Johan Mackenbach, 'Income inequality and population health', British Medical Journal, 2002

W & P also mention the study by Kondo et al., published in the BMJ in 2009. They have a particular fondness for this study, which measured self-reported health. They cited it during the Royal Society of Arts debate and referenced it in their response to Peter Saunders. They also mentioned it in their response to an article I co-authored in the Wall Street Journal. In the latter, they insisted that it "shows unequivocally that inequality is related to significantly higher mortality rates."

In fact, the study concludes that:

The results suggest a modest adverse effect of income inequality on health, although the population impact might be larger if the association is truly causal... The findings need to be interpreted with caution given the heterogeneity between studies

This paper certainly gives more support to W & P's hypothesis than most, but it is anything but unequivocal.

5. You use the high rate of teen births in Portugal (in 2002) as proof that inequality is related to teen births. Why do you not mention that abortion was illegal in Portugal until 2007?

Wilkinson & Pickett: We do indeed show that teenage births are related to income inequality in rich countries, as have UNICEF. This is not dependent on Portugal; indeed if we exclude Portugal the relationship with inequality is slightly stronger, not weaker. In the USA, unlike internationally, data on teenage conceptions were available so we use those, rather than births, as they are unaffected by state differences in access to abortion, and we show the same robust relationship with inequality.

The relationship is not stronger without Portugal. Nor could it be, since Portugal is an unequal country with a high rate of teen birth (primarily the result of its high rate of teen marriages and low abortion rate). With Portugal dropped from the analysis, the r-squared drops from an already feeble 0.10 to 0.089.

I do not suggest that the correlation is dependent on Portugal, only that a ban on abortion is going to have a major effect on the birth rate and is an example of the kind of real-world differences that are routinely ignored in The Spirit Level. Throughout The Spirit Level, W & P refuse to acknowledge social, demographic, historical and cultural differences between nations unless those differences can be used to plug gaps in the theory.

For example, when Finland is seen to have a high rate of homicide, they are quick to point out that it has a high level of gun ownership, but, absurdly, they do not give the same benefit of the doubt to (unequal) places like Israel and the United States.

In the case of Portugal, two major, common sense explanations for the high level of teen births are staring them in the face (the other being Portugal's high rate of teen marriages) but since the high Portuguese figure superficially supports their hypothesis, these confounding factors are never acknowledged.

As I acknowledge in The Spirit Level Delusion, the UNICEF report mentions inequality as one possible explanation for teen births but it makes it clear that it is not the primary cause. As Peter Saunders has shown, English speaking countries tend to have higher teen births. The UNICEF document makes it clear that cultural differences provide a better explanation for teen birth rates than inequality. The low rates of teen births in Singapore and Hong Kong (not shown in The Spirit Level) give further support for this, as does the fact that the only non-Anglo nation with a higher rate of teen births is Portugal for the reasons given above.

6. Why do you not include the crime rate in your index of health and social problems? Is it because the crime rate tends to be higher in 'more equal' countries?

Wilkinson & Pickett: It has often been pointed out that homicides are one of the few crimes which can be compared reliably between countries. Comparisons of other kinds of crime are affected by differences in the law, in reporting, and by other extraneous influences. Car crime, for instance, is affected by the number of cars and rape is dramatically affected by reporting (see our answer to Q 19 below. While there are some research papers showing relationships between inequality and property crime, there are no sources of data (including those used by Snowdon) which deal adequately with these problems. Hence, we confined our attention to adult and juvenile homicide rates. There are more than 50 studies showing that inequality is related to violence, see for example the review by Hsieh and Pugh 25 and the recent study by Elgar and Aitken.

I mention the potential pitfalls of comparing recorded crime data in The Spirit Level Delusion, which is why I also show the results of the EU Crime Survey. The Crime Survey uses the same methodology for all countries and is based on people's experience of crime, whether recorded or not. Both data sets indicate higher levels of crime—particularly property crime—in more equal societies.

7. Why do you say that homicide is inversely related to suicide when there is no evidence for this?

Wilkinson & Pickett: In fact, there are several pieces of research which show that homicide rates are inversely related to suicide, see for example (44) (45)

Having spent so long fact-checking The Spirit Level, it came as no great surprise when I turned to the first study referenced by W & P and found that its conclusion read:

The overall correlation between homicide and suicide rates was weak and statistically insignificant

It is certainly true that homicide rates are higher in Africa and the Americas (this is confirmed in the second study they reference—see below), while suicide rates are higher in Europe.

Perhaps W & P would argue that this graph shows that suicide is inversely associated with homicide. I think most people would say that it shows that there is simply a much higher homicide rate in Africa and the Americas. There is reason to believe that rising prosperity leads to lower homicide rates and higher suicide rates. But when we compare the wealthy countries that are the focus of The Spirit Level, there is no correlation between suicide and homicide (see The Spirit Level Delusion, p. 82).

8. Why do you suggest that people in more equal countries give more to charity when the reverse is true?

Wilkinson & Pickett: We do not say that people in more equal countries give more to charity - instead we show that more equal countries donate more in development aid to foreign countries. We do cite Eric Uslaner’s work which shows that people who have high levels of trust are more charitable. Snowdon presents data from the Charities Aid Foundation, which suggests that more unequal countries (especially the USA) have higher levels of individual charitable giving. However, as the Charities Aid Foundation points out, charitable giving in the USA is heavily influenced by tax policy, and may also be a response to the exceptional need created by the US lack of social security systems. Only 3% of US charitable giving goes overseas, so total US donations to overseas development are substantially lower than other rich countries.

Low levels of US government aid are partly a reflection of low trust in government (strongly related to inequality) and also of a lack of social security and welfare provision. Together these shift the onus of support to wholly inadequate private charitable giving.

On page 60 of The Spirit Level, Wilkinson and Pickett write that:

"Not surprisingly, just as individuals who trust other people are more likely to give to charity, more equal countries are also more generous to poorer countries."

Bearing in mind that, at this point in the book, W & P have just 'proved' that people in egalitarian societies are more trusting of other people, how else is the reader supposed to interpret this sentence, other than as a claim that people in more equal countries give more to charity?

But they don't. They give less to charity, for reasons that are well-understood. The Charities Aid Foundation (CAF) certainly does point out that the USA's tax system encourages donations to charity. Are Wilkinson and Pickett suggesting that this is a bad thing? It seems that way. (nb. Only Sweden, Finland and Austria do not incentivise charitable giving).

The CAF also notes that people in high-tax countries are less likely to give to charity. This is hardly surprising, since people are less likely to give to charity if (a) they have less disposable income, and (b) they live in a society which expects the state to take responsibility for such matters. I address both issues in my book and quote the CAF.

Wilkinson and Pickett reveal their political bias with their dismissive attitude towards voluntary, private charity and their preference for publicly funded, compulsory aid. They are fundamentally wrong about all their assumptions given above. Low levels of government aid are not a response to lack of trust in government—the government decides the level, after all. Instead, they are the result of lower levels of taxation and a historical emphasis on private philanthropy. W & P are also wrong to say that total US aid (private + public) is "substantially lower" than that of other countries. The USA is consistently in the top 10 in both per capita terms and in absolute terms.

And they are wildly wrong when they make the unreferenced claim that only 3% of US donations goes overseas. This is just the kind of causal disregard for the truth that makes fact-checking The Spirit Level such an exhausting affair. Of the $307 billion the US gave to charity privately in 2008, $116 billion went overseas. That is 38%, not 3%. And while Americans prefer private donations to state-funded aid, the USA gives far more than 0.7% of its GDP to the developing world. (0.7% being the United Nations target.)

9. Why did Kate make a video called ‘Why Cubans live longer than Americans?’ when all the sources show that life expectancy in Cuba is lower than in the USA?

Wilkinson & Pickett: Kate was not consulted about the title for this online clip from a short interview. What she actually said was that countries such as Cuba, Costa Rica and some poorer European countries have life expectancy as high, or higher than, the USA. In fact, in the 2006 revision of the United Nations World Population Prospects report, for 2005-2010, infant mortality rates in Cuba were 5.1 per 1000 live births, compared to 6.3 for the United States, and life expectancy was in Cuba was 78.3 years, compared to 78.2 years in the USA.

It is difficult to believe that Pickett would have no say about the title of a video she presented, or would have no power to rename or withdraw the video once it was given a misleading title. But whoever named it can hardly be blamed, since she does indeed claim that Cuba and Costa Rica have life expectancies that are "as high or higher than the United States."

W & P's reference to the World Population Prospects report is another example of their habit of data-mining to find the 'right' figures. As they must know, that particular report gives a prediction, it is not a real figure. More reliable figures for life expectancy come from the UN HDR—the preferred source used in The Spirit Level. All of these reports show life expectancy being higher in the USA than in Cuba and Costa Rica. The most recent edition shows that life expectancy is 79.1 in the USA and 78.5 in Cuba. Costa Rica's life expectancy is 78.7.

10. Why do you write about "increased family break-down and family stress in less equal countries" when divorce and single-parent households tend to be more common in more equal countries?

Wilkinson & Pickett: Although lone parent families are not more common in more unequal countries, changes in income inequality are correlated with rising divorce rates in US counties.

This evades the question. The facts show that divorce is more common in more equal countries, and the Scandinavian countries have amongst the highest rates of lone parent families (as do some Anglo-Saxon countries). It is simply untrue to say that there is "increased family break-down and family stress in less equal countries".

11. Why do you say that community life is weaker in less equal countries when these nations have more people involved in community organisations (charities, sports clubs, environmental groups etc.)?

Wilkinson & Pickett: Robert Putnam’s measures of ‘Social Capital’ are based on membership of voluntary and community associations of the kind you mention. Both in his earlier study of the Italian regions and in his study of the American states he shows there is a very strong tendency for the more equal regions and states to have stronger community ties measured in this way. Looking at changes over time in the US as a whole he also says:

"Community and equality are mutually reinforcing... Social capital and economic inequality moved in tandem through most of the twentieth century. In terms of the distribution of wealth and income, America in the 1950s and 1960s was more egalitarian than it had been in more than a century. ...those same decades were also the high point of social connectedness and civic engagement. Record highs in equality and social capital coincided. Conversely, the last third of the twentieth century was a time of growing inequality and eroding social capital. By the end of the twentieth century the gap between rich and poor in the US had been increasing for nearly three decades, the longest sustained increase in inequality for at least a century. The timing of the two trends is striking: somewhere around 1965-70 America reversed course and started becoming both less just economically and less well connected socially and politically." p.359

Sociologists distinguish between generalized trust (trust of people with whom we do not have an intimate relationships) and particularized trust (trust of people like ourselves). Generalized trust is related to social capital, and many researchers, including Putnam, have linked these measures of social capital to greater equality. Indeed, they have shown that it is inequality that affects trust, rather than the other way round.

Again, this does not answer the question. The international evidence shows that people in less equal countries are more likely to be members of clubs, societies, sports associations, religious groups etc. The only exception is trade union membership, which is often compulsory or strongly 'encouraged'. The graph below shows data from the World Values Survey.

What Putnam shows is that membership of these kinds of groups has declined in the United States over the last fifty years (as it has elsewhere). But Putnam never endorses the theory that inequality is the cause of the decline in club membership or social capital.

Indeed, W & P's selective quoting from Putnam's Bowling Alone is a good example of how they provide the illusion of an academic consensus where none exists. In The Spirit Level, they quote the same passage as the one quoted above, with the same sections deleted. The unwary reader might interpret this quote as evidence that Putnam believes that inequality leads to less social capital.

But, as ever with W & P, it is what they do not show that is most instructive. The unabridged first line of this quote reads: "Community and equality are mutually reinforcing, not mutually incompatible." After the last line W & P quote, Putnam concludes: "This pair of trends illustrates that fraternity and equality are complementary, not warring values."

As these words suggest, Putnam is not arguing that income equality necessarily increases social capital, he is merely arguing that the former does not damage the latter. This is obvious from the section heading which asks the question: 'Is social capital at war with equality?'

Why would he ask that question? Because, as Putnam points out: "the abundant social capital of the 1950s was often exclusionary along racial and gender and class lines. Generally speaking the haves engage in much more civic activity than the have-nots." Because of this, it is sometimes argued that left-wing attacks on elitist social institutions weaken some forms of community life. Putnam argues that these fears are ill-founded, and he says the positive correlation between equality and social capital in the USA since the Second World War "powerfully contradicts the view that community engagement must necessarily amplify inequality."

But Putnam is far more cautious in claiming a causal link between income equality and social capital than W & P. In fact, this brief passage is the only part of his 500 page book that evens mentions income equality (R. Putnam, Bowling Alone, 2000; pp. 358-60). When he sums up the evidence to explain why community life has broken down in the USA since the 1950s, he identifies four factors ('generational change', 'television', 'work' and 'sprawl' - p. 284). He does not include inequality.

12. Do you accept that the World Values Survey data show no correlation between 'happiness' and inequality, but a strong correlation between 'happiness' and income?

[There are so many points to make about W & P's answer here that I have split it up]

Wilkinson & Pickett: We accept that there is no relation between inequality and WVS measures of happiness, but among the rich countries neither is there a relation between happiness and Gross National Income per head (see our figure 1.2 in The Spirit Level).

W & P's claim that there is no relationship between happiness (as measured by the World Values Survey) and Gross National Income is incorrect. As can be seen from the graph below, there is a clear correlation, even at a very high level of economic development.

W & P never show this graph. Instead, they use a graph that shows rich and poor countries together (Spirit Level, p. 9), which obscures what is shown above. Consequently, they are able to begin their book by claiming that "happiness levels fail to rise further as rich countries get still richer". This is a crucial part of their argument, since it suggests that economic growth has "done its work"and can therefore be curtailed. It is, however, factually incorrect.

The other important thing about the happiness surveys is that they show no relationship with inequality. This is a crucial observation, since it is powerful evidence that more equal societies are not happier.

During the Royal Society of Arts debate, Richard Wilkinson responded to this evidence by claiming that happiness does not have a social gradient and, therefore, would not be affected by levels of inequality. This is not true. Any number of studies have shown that the rich are happier than the poor eg. Easterlin (1974). They have, however, now acknowledged this...

In our debate at the RSA, Richard meant to say that happiness and income have a reverse social gradient, rather than no social gradient. The correlation between income and happiness among individuals within countries has been shown to be a relationship with relative income and social status.

The correction is welcome* but the subsequent argument is weak. There are many reasons why the rich are happier than the poor. In part, their absolute income allows them to afford a better standard of living and, in part, their relative income allows them to compare themselves favourably to their peers. While both are important, the material benefits of absolute income receive short shrift in The Spirit Level. W & P focus only on relative income and claim that richer people are happier only because money buys status and status symbols. This is opinion, not fact.

It has also been shown that additional income makes much more difference to the happiness of the poor than the rich. This would suggest that redistribution would improve over-all happiness.

No. It suggests that additional income would improve the happiness of the poor. We should, therefore, pursue a system that will maximise increases in the incomes of the poor. There is no evidence that the zero-growth egalitarianism proposed by W & P will do that.

But the key argument in The Spirit Level is that the poor would become happier if the rich become poorer, even if the poor got no richer in the process. In other words, rounding up and deporting every millionaire in Britain would, in itself, be enough to improve social outcomes, even if no one got richer as a result. This is where W & P depart from the bulk of the scientific literature and, I would argue, from common sense.

Several economists who study happiness (e.g. Blanchflower and Oswald) show that, in sub-national analyses, more equal societies, for example more equal US states, are happier.

The majority of happiness studies have shown that inequality has no effect on happiness, which is why the happiness studies are not mentioned in The Spirit Level. (See, for example, reviews by Clark and Senik (2010) and Hopkins (2008).) Nor do Blanchflower and Oswald say that more equal states or countries are happier. This is a complete misrepresentation of the literature.

International comparisons of subjective variables, such as happiness, are notoriously unreliable (for example, self-reported health appears better in countries with higher death rates) This is why in The Spirit Level we concentrated very largely on objective measures of health and wellbeing.

Since the happiness surveys show no correlation with inequality and a strong correlation with income, it is perhaps unsurprising that W & P now choose to distance themselves from them. It is a shame they felt the need to put this "notoriously unreliable" data at the heart of the first chapter of their book. Note also, that the trust survey—upon which they base so many of their arguments—is a wholly subjective and self-reported measure. They also put great faith in the Kondo study (see question 4) which studies self-reported health.

[*A "reverse social gradient" implies a reverse relationship ie. that the poor are happier. Since even W & P cannot believe this (surely?), I assume this to be a slip of the pen.]

13. On page 19 of The Spirit Level, you say you included alcohol addiction as a 'health and social problem', but you never discuss it in the rest of the book. Is this because the highest rates of alcoholism are in Scandinavia?

Wilkinson & Pickett: It is important to distinguish between alcohol use and alcohol abuse. Alcohol use is difficult to measure and often has no social gradient – consumption tends to be higher in higher social classes. This is in marked contrast to binge and problem drinking. We include alcohol abuse (as measured by surveys of mental illness that cover drug and alcohol addiction) in our Index of Health and Social Problems, and have previously demonstrated a significant relationship between deaths from alcohol-related liver disease and income inequality in US states.

I agree about making a distinction between per capita alcohol consumption and overall alcohol consumption, but several international surveys of mental illness surveys have shown that the more equal Scandinavian countries have the highest levels of alcohol abuse. It would be interesting to see what W & P's alcohol abuse graph looks like. It does not appear in The Spirit Level and the data is not included in their spreadsheet.

14. Why do you show no data about the (high) prevalence of mental illness in Scandinavia?

Wilkinson & Pickett: The World Health Organization has not yet produced internationally comparable data on mental illness for Scandinavian countries, but we eagerly await such data. In the absence of robust estimates from the WHO, we know of no high quality data to justify the suggestion that Scandinavian countries have a higher prevalence of mental illness.

W & P's mental illness graph provides one of the most egregious examples of data-mining in The Spirit Level. Much more evidence for mental illness prevalence exists than is shown in The Spirit Level and, although W & P are implying otherwise, they do not confine themselves to "robust estimates from the WHO". The figures they use for the UK, Australia, New Zealand and Canada (all less equal countries) come from other sources. When more than one source is available, W & P consistently pick the figure that best suits their hypothesis. As I explain in The Spirit Level Delusion, there are serious questions about the reliability of some of the figures from the WHO study, which the study's authors acknowledge.

I don't claim that rates of mental illness are necessarily "higher" in Scandinavia, but the available evidence suggests that they are as high as in the United States. For example, a large study of all four Nordic states concluded:

Overall, it can be concluded that the prevalence rate of generalized anxiety disorder and major depression in different European countries, including Denmark, Finland, Norway, and Sweden, are as high as those found in the United States. (‘Prevalence of generalized anxiety disorder in general practice in Denmark, Finland, Norway, and Sweden’, P. Munk-Jorgensen, Psychiatric Services, 57 (12), December 2006; p. 1738-44)

Similarly, a study of mental health in Norway compared rates of the most common mental disorders with those in the USA and found "almost identical rates for alcohol abuse, major depression, and social phobia in the two countries." (‘A Norwegian psychiatric epidemiological study’, E. Kringlen et al., American Journal of Psychiatry, 2001, 158; pp. 1091-98)

Incidentally, the largest systematic review of the prevalence of mental disorders in the EU (Wittchen & Jacobi, 2005 - summarised here (p. 47)), found the 12 month average to be 27%—ie. almost identical to estimates from the USA.

15. If equality creates good health, why does Denmark currently have the lowest life expectancy of any country in your list?

Wilkinson & Pickett: As with our other analyses, we (unlike our critics) do not pick and choose different countries to include or exclude according to whether or not their outcomes fit the inequality data. Denmark does indeed have much lower life expectancy than we would expect given its level of inequality. We have never claimed that income inequality is the only cause of worse health and social problems in a society. There will always be countries that do a bit better or worse on any outcome than we might predict given their level of inequality. Some researchers have attributed Denmark’s relatively poor health to its high levels of smoking.

Denmark doesn't have a particularly high level of smoking (see page 24 of SLD) and there is surprisingly little correlation between high smoking rates and low life expectancy when whole nations are compared. This only serves to highlight the problem of looking for the effect of one variable amongst aggregate data.

The simple fact is that the Scandinavian countries all have a very low level of inequality but vary wildly when it comes to life expectancy. Using data from the most recent UN HDR, out of 28 countries Sweden comes 8th, Norway comes 12th, Finland comes 19th and Denmark comes 27th.

Japan comes 1st, and this is the jewel in W & P's crown since Japan has an even lower level of inequality (by their measure, at least). But very unequal Hong Kong comes 2nd. Of course, readers of The Spirit Level will not know that because—although W & P "do not pick and choose different countries to include or exclude according to whether or not their outcomes fit the inequality data"—Hong Kong is never shown.

16. Why were Singapore and Hong Kong excluded from your graph on obesity?

Wilkinson & Pickett: The International Obesity Taskforce did not report data on obesity for Singapore in the 2002 report which was available when we were writing The Spirit Level. Hong Kong is not a nation state but even if it were it does not meet our inclusion criteria (see point 1).

The Singapore figure was published in 2004. The IOTF currently cites this figure so presumably we can expect it to appear in future editions of The Spirit Level.*

Hong Kong's somewhat unusual political status is no reason to exclude it. It is a country and both the World Bank and the United Nations treat it as such and collect data for it as a separate entity. It is certainly a separate and distinct society and The Spirit Level's subtitle is 'Why More Equal Societies Almost Always Do Better'. If US states fall under the category of separate societies, it is surely reasonable to include Hong Kong.

Why wouldn't Hong Kong meet the inclusion criteria? It has a population of over 7 million, it has sound data on inequality and came 16th in W & P's preferred list of rich countries.

* UPDATE 2011: The second edition is out and it is still missing.

17. Do you accept that the "correlation" between trust and equality rests entirely on figures from the four Nordic countries and that there is no pattern amongst the remaining 19 nations?

Wilkinson & Pickett: Absolutely not. These countries are NOT outliers, but lie on the trend line. However, even if they are excluded there is still a statistically significant correlation among the remaining countries (r=-0.46) as well as among US states where the correlation between trust and inequality is also highly significant (r=-0.7).

Again, this depends on which data are used. W & P's trust data come from the 1990s. If you use World Values Survey data from the 2000s, it is clear that the Scandinavian countries are outliers. The correlation disappears when they are excluded (see below). Even if you prefer W & P's older data set, their correlation is extremely weak.

18. Why do you say that young people "defer sexual activity" in more equal countries when there is no evidence for this?

Wilkinson & Pickett: We don’t say that people defer sexual activity in more equal countries – we simply discuss Professor Jay Belsky’s theory about quality versus quantity reproductive strategies which biologists have identified in many species.

W & P certainly do discuss Jay Belsky's theory that—as they put it—"people who grow up learning 'to perceive others as trustworthy, relationships as enduring and mutually rewarding and resources more or less constantly available' would mature later, defer sexual activity, be better at forming long-term relationships and invest more heavily in their children's development."

W & P precede this discussion by saying "there seem to be additional reasons why teenage motherhood is sensitive to degrees of inequality in society". They follow it by saying: "So there may be deep-seated adaptive processes which lead from more stressful and unequal societies." Apparently the reader should not infer from this that women in more equal societies defer sexual activity?!

19. If greater equality makes countries less violent and more law-abiding, why does Sweden have the highest rate of rape and theft of any country in your list? Why does Finland have the highest murder rate in Europe?

Wilkinson & Pickett: As we discuss in The Spirit Level, there are multiple influences on health and social problems, and income inequality is only one factor (albeit a strong and robust factor, demonstrated in more than 50 studies) affecting murder rates. Finland has a higher rate of homicides than we would predict, given its level of inequality, probably because of its high level of gun ownership. If we control for gun ownership in US states, the relationship between inequality and homicides actually gets stronger. For crimes other than homicides, comparing crime data among different countries is problematic, due to reporting differences. It seems sensible to assume that rape is more likely to be reported in societies where women’s status is higher.

It is not true that "more than 50 studies" have found a "strong and robust" association between inequality and homicide. Again, W & P mention a third variable (gun ownership) when they discuss Finland but do not give the same benefit of the doubt to Israel and the USA. In The Spirit Level, they do the same when trying to explain how the most equal state (Alaska) has one of the highest rates of homicide. They also make the questionable assumption that murders in America are carried out with legal firearms.

The assumption that Sweden has the highest rate of recorded rape because women are more likely to report sexual assaults is pure supposition.

20. Since when has the definition of a tax haven been a country with fewer than 3 million inhabitants? Isn't this just an excuse to leave out Slovenia?

Wilkinson & Pickett: The cut off for a small country has to be defined somehow – countries with populations around our 3 million cut-off point include Slovenia, Namibia, Lesotho, and Botswana. Slovenia is the only rich country with close to 3 million inhabitants excluded from our analyses. What happens if we add it in? Not much – the correlation between income inequality and homicides is r=0.42 (p=0.04) with Slovenia in, and r=0.43 (p=0.04) with Slovenia out. For imprisonment, the correlation with Slovenia in is r=0.66 (p<0.001), with Slovenia out, it is r=0.65 (p<0.001)….etc

No, the cut-off for a small country does not have to be defined somehow. A cut-off is completely unnecessary. All we need to know is which countries are tax havens (is Switzerland not a tax haven?). All the 3 million cut-off does is exclude Slovenia.

And, yes, including Slovenia often doesn't make a great deal of difference. That's isn't the point. We don't pick and choose the countries on the basis of whether they will make a difference. We include them so we have the full range of rich societies upon which to base our conclusions. Since The Spirit Level's conclusion is that "it falls to our generation to make one of the biggest transformations in human history" (p. 265), it would prudent to make sure the assumptions it is based on are not plucked out of the air.

It should also be noted that in one of their published studies, Wilkinson and Pickett "included only countries that had income inequality data and were among the richest 50 in the world and excluded those with populations of 50 in the world and excluded those with populations of less than two million to avoid possible tax havens." This allowed them to include Slovenia which, for the criterion studied in that paper, happened to strengthen the desired relationship. The switch from two million in this study to three million in The Spirit Level did not weed out any tax havens and served only to exclude Slovenia.

And finally...

A word about the scientific literature. W & P are fond of claiming that their work is backed up by 100s of peer-reviewed studies. In a recent letter to The Guardian, for example, they once again referred to "hundreds of other academic research papers which show similar patterns."

Do not be fooled. Very few of the studies referenced in The Spirit Level claim that health or social problems are caused by income inequality per se (as opposed to absolute income or other socio-economic factors). Of the few that do make such a case, many were written by Richard Wilkinson and/or Kate Pickett (they refer to no fewer than twelve of their own studies in The Spirit Level).

The bulk of the references are to newspaper articles, opinion pieces, other people's books, studies that discuss specific issues (eg. stress, violence, obesity) and the sources of the raw data (eg. UN, OECD). Often the studies referenced give equivocal support or contradict W & P (see Questions 4 & 7, for examples). The only area which has a significant body of scientific literature is health and inequality, and much of it disagrees with Wilkinson's hypothesis. As Wilkinson admitted in a recent interview with the magazine International Socialism, there is virtually no evidence from other academics to support the bulk of the claims made in The Spirit Level.

Wilkinson: "There are about 200 papers on health and inequality in lots of different settings, probably 40 or 50 looking at violence in relation to inequality, and very few looking at any of the other things in relation to inequality. In a way, the new work in the book is all these other variables—teenage births, mental illness, prison populations and so on—and the major contribution is bringing all of that into a picture that had previously been just health and violence."

These are, then, very much W & P's own ideas. Although The Spirit Level has launched their theories into the popular consciousness, they find little support in the scientific literature. It is no surprise, then, that their book has received a much cooler reception from academics (see below) than from ex-politicians and journalists.

"The bottom line is that this is a well-written, stimulating polemic. It nevertheless suffers from the same problems as one-trick ponies: if the one trick does not impress you, the show is a failure. Wilkinson and Pickett’s trick simply does not hold up to empirical scrutiny. When assessing this book as a contribution to the debate on the “right” level of income differences in modern society, it is a highly interesting, sympathetic attempt at addressing some of the important problems of Western societies. Yet, when assessing this book from a scientiﬁc point of view, one is forced to conclude that it is a failure."

— Christian Bjornskov, Professor of Economics, University of Aarhus, Population and Development Review, June 2010

"Wilkinson and Pickett have no time for nicely balanced judgements. They believe that the evidence they present shows beyond doubt that more equal societies ‘do better’, and they are also confident that they have the right explanation for why this is so... Their case is by no means so securely established as they try to make out... it has been called into question by other leading figures in the field – a fact that WP might have more fully acknowledged... WP’s inadequate, one-dimensional understanding of social stratification leads to major problems in their account of how the contextual effect is produced."

— John Goldthorpe, Emeritus Professor of Sociology, Nuffield College, Oxford; ‘Analysing social inequality’ European Sociological Review, 2009

"The evidence in The Spirit Level is weak, the analysis is superficial and the theory is unsupported."

— Peter Saunders, Emeritus Professor of Sociology, University of Sussex, Beware False Prophets

"The book will probably irritate most economists, including those like me who are sympathetic to its basic stance... source of irritation is the authors’ apparent belief that the application of regression methods to economic and social statistics is as novel to social science as it apparently is to medicine. The evidence presented in the book is mostly a series of scatter diagrams with a regression line drawn through them. If you remove the bold lines from the diagram, the pattern of points mostly looks random, and the data dominated by a few outliers... An obvious conclusion is that there are many societies which perform well in terms of their own criteria. America, Sweden and Japan are just different from each other. Their achievements are not really commensurable. But Wilkinson and Pickett are not content with this relativist position."

— John Kay, former Director of Institute of Fiscal Studies and Professor of Economics at London Business School, Financial Times, 2009

UPDATE

Sanandaji et al. have also written a detailed response to Wilkinson and Pickett's rebuttal of their criticisms. If you are interested in the debate about The Spirit Level (and, if you've got this far, you probably are!), I warmly recommend it. Click here.

Chopping and changing

2011-01-28T13:06:00.001Z

The new postscript to The Spirit Level finds Wilkinson and Pickett accusing their critics of “selectively removing countries on the grounds that they were outliers.” Outliers do indeed play an important part in several of The Spirit Level’s graphs. The correlation between inequality and homicide rests entirely on the USA being an extreme outlier. The correlation between inequality and obesity depends entirely on Japan and the USA being outliers (as well as the exclusion of Singapore, Hong Kong and South Korea, all of which have similar rates of obesity to Japan). The correlation with trust depends entirely on the Nordic nations being outliers.

The significance of this should not need underlining. To take homicide as an example, there is no evidence of a relationship between inequality and homicide when 22 countries of the countries are studied. The 23rd country—the USA—has a much higher rate and pulls the regression line upwards dramatically. Using this distorted regression line as evidence that inequality causes murder means ignoring the data from 22 countries in favour of data from just one. There are many reasons why the USA has a high murder rate, but if inequality was the root cause, we would expect to see it affecting the other countries. It doesn’t, and excluding the USA as an outlier demonstrates this.

If we were presented with a graph showing low levels of participation in baseball in 22 countries but a much higher figure for the USA, few of us would conclude that there was a true causal relationship between inequality and baseball. Americans just play a lot more baseball. And yet, for several of The Spirit Level’s graphs, outlying data of this type are used as proof of a causal relationship despite the great majority of the countries being totally unaffected by the supposed cause.

Wilkinson and Pickett feign ignorance about the importance of outliers. In their postscript, they portray testing for outliers as an underhand trick to exclude unfavourable data. It is, of course, nothing of the kind. The point of testing for outliers is not to “selectively remove countries” and then present the result as the ‘real’ graph, but to see if the relationship holds up without the outlier being present. In Beware False Prophets, Peter Saunders explains how and why statisticians use box plots to identify outliers. He then shows, as I do in this book, that the trend line for homicide is being thrown out by a single extreme outlier.

It is fantastically implausible to think that Wilkinson and Pickett are not aware of the importance of outliers in statistics. In fact, we know that they are because when they find a reasonably strong statistical relationship (for rates of imprisonment) they write: “Even if the USA and Singapore are excluded as outliers, the relationship is robust among the remaining countries.” They make no such guarantee of their other graphs, for the simple reason that they are not robust.

One of the dangers of not testing for outliers is that your trend line will become skewed and no longer reflect reality. Wilkinson and Pickett focus on their trend line to such an extent that they forget what the actual data are telling them. In the last chapter of The Spirit Level, Wilkinson and Pickett claim that if Britain reduced income inequality to the same level as Sweden, Finland, Japan and Norway, its murder rate would fall by 75%. This prediction goes far beyond what the data show. (Even if the association was real, their correlation coefficient tells them that inequality accounts for less than half the difference, and yet they assume it accounts for 100% of the difference—a very basic error.)

Worse still, they are basing their prediction entirely on their trend line, which tells them that Britain should have a much higher murder rate than it does. But that trend line has become hopelessly skewed by the USA. Britain actually has a lower murder rate than Sweden and Finland and has a lower murder rate than the average of those four ‘more equal’ nations.

The irony of Wilkinson and Pickett accusing their critics of picking and choosing which countries to study will not be lost of readers of this book. Wilkinson was being criticised for his selective use of data long before The Spirit Level hit the shelves. Their justification for confining their analysis to 23 countries is because “these countries are on the flat part of the curve at the top right in Figure 1.1 on p. 7, where life expectancy is no longer related to differences in Gross National Income.” Quite so, and it was that very graph which first alerted me to the fact that Wilkinson and Pickett had excluded several countries. (The image below is a close-up of the richest countries in that graph with GDP increasing from left to right.)

South Korea, Hungary, Slovenia and the Czech Republic all appear on that graph as being as rich or richer than Portugal. It was not me, but Wilkinson and Pickett, who arbitrarily decided that Portugal was ‘rich enough’ to merit inclusion. All I have done in this book is include countries of comparable or greater wealth than Portugal as shown in Wilkinson and Pickett’s own graph. Without a convincing justification for why places like the Czech Republic and South Korea cannot be considered “rich market societies”, we must ask the next question: why do these societies conspicuously fail to fit Wilkinson and Pickett’s theory? The United Nations classes these countries as being of “very high human development”, why doesn’t The Spirit Level?

Their insistence on never having “picked problems to suit our argument” is rather undermined by, for example, their focus on public foreign aid at the expense of private aid, or by their emphasis on imprisonment rather than crime. Their claim to “never pick and choose data points to suit our argument” is at odds with references 2 and 6 in The Spirit Level which show one year’s data being used for one graph and another year’s data being used for the next, even though the subject matter—life expectancy—is the same.

As for using “the same measures of inequality” (as they said they did in an article in Prospect magazine), they address this early in The Spirit Level, saying:

To avoid being accused of picking and choosing our measures, our approach in this book has been to take measures provided by official agencies rather than calculating our own.

This is no great claim to integrity. It would be very odd if they started developing their own bespoke measure of inequality. But if they really wished to “avoid being accused of picking and choosing” they would have used the same official measure throughout. In fact, they use no fewer than five different measures of inequality in The Spirit Level.

Having correctly explained to the reader that the Gini coefficient is “the most common measure” which is “favoured by economists”, they proceed to ignore the Gini in favour of comparing the top and bottom 20% when making international comparisons. They then switch to the Gini coefficient when looking at US states and then use a completely measure when comparing working hours (p. 229). They then adopt a measure which compares the bottom and top 10% (p. 240) and, finally, in their new edition, measure inequality in reference to the top 1% (p. 296).

The effect of this chopping and changing can be seen by comparing the graph on page 240 to the graph on page 296 (of the new edition). The first graph shows that inequality in the USA has fallen since its peak in the early 1990s; the second graph shows that inequality in the USA rose sharply in the 1990s and peaked at the time of the 2008 recession. Wilkinson and Pickett’s aim in the postscript is to demonstrate a correlation between inequality and the financial crashes of 1929 and 2008. They write that “both crashes happened at the two peaks of inequality”. Either they have forgotten, or they are hoping the reader has forgotten, that they wrote in the previous chapter that inequality in the USA “peaked in the early 1990s”.

Whilst there is nothing wrong with using the share of wealth held by the top 1% as a measure of inequality, this is the only time it is used in The Spirit Level. This is unsurprising since under this measure Norway and Denmark are less equal than the USA. It does, however, demonstrate how Wilkinson and Pickett switch reference points to suit whatever argument they are making at the time.

A right-wing conspiracy?

2011-01-27T11:41:00.000Z

Having hastily reinvented themselves as bearers of the consensus (see earlier post), it is a simple matter for Wilkinson and Pickett to portray those who have put their claims to the test as deniers, right-wing extremists and paid lackeys of industry. It is an impressive trick for a long-standing member of the Socialist Health Association to write a book which concludes with a rousing political call-to-arms while forming two left-wing pressure groups and penning articles in The Guardian about how “broken Britain is Thatcher’s bitter legacy” to accuse other people of being “politically motivated”. This unlikely defence has, however, been remarkably successful.

Wilkinson and Pickett’s first response to the criticisms made in Peter Saunder’s Beware False Prophets was from page one from the manual of knee-jerk student politics. They called him a racist and described his publishers at the Policy Exchange, the manifestly moderate centre-right think tank, as being from the “far-right”. This was no slip of the tongue, since Wilkinson has repeated the slur whilst touring his book in Canada (“then the attacks started coming from the far-right”). Wilkinson can hardly be unaware that the term “far-right” is used almost exclusively to describe neo-Nazis and fascists. That he immediately resorted to malicious defamation of a fellow Emeritus Professor, and former colleague at the University of Sussex, was an early sign that the debate about The Spirit Level was going to be ugly.

It was also a sign that Wilkinson and Pickett would spread their net far and wide in seeking to disparage their opponents. In the new postscript, they write about “the bans on smoking in public places (implemented in Scotland, parts of the USA and Canada, Rome, Ireland, and England); which in each case have been followed by declines in death rates and have saved thousands of lives.”

This requires a little background information. In recent years, a number of studies have been published purporting to show a large drop in the heart attack rate in the aftermath of a smoking ban. In Scotland, for example, it was claimed that the rate of acute coronary syndrome fell by 17% following the implementation of smokefree legislation. Oddly, however, the study was based on extrapolations from a selection of hospitals, rather than the admissions records for all Scottish hospitals, which were freely available. When the real figures from the NHS were examined, it became clear that there had not been a drop of 17%, or anything like it.

Today, several years after the ban came into effect, it is quite apparent that the smoking ban had no apparent effect on the rate of acute coronary syndrome in Scotland. A number of other studies have claimed to find a drop in heart attacks following the enactment of smoke-free legislation, but whenever hospital admissions data have been publicly available there has, without exception, been no indication of a significant decline. A recent study—the largest ever conducted on the subject—found that “large short-term increases in myocardial infarction incidence following a smoking ban are as common as the large decreases reported in the published literature”. The disproportionate number of studies finding a decline in numbers is, the authors suggested, the result of publication bias and retrospective data-mining.

I was one of a number of journalists to write articles about the Scottish ‘heart miracle’ and similar studies elsewhere. I was not alone. When the Scottish hospital records were released in 2007, the BBC reported it with the headline ‘The facts get in the way of a good story’. The Times included in its end-of-the-year ‘Worst Junk Stats of 2007’ feature. Michael Siegel, a Professor at Boston University School of Public Health and a long-standing campaigner for indoor smoking bans, said that "these data are just so unconvincing that even I cannot, with any conscience, look at them and opine that they show a significant short-term effect of smoking bans on heart attack admissions". He blamed the result on "unconscious bias".

If this seems wildly off-topic, it is. Wilkinson and Pickett’s reason for going off on this tangent is to mark me down as some sort of tobacco industry lobbyist just for having written about such issues. They are wise enough not to risk libel by stating that explicitly, but the implication is allowed to hang in the air.

Upon this thread of innuendo, Wilkinson and Pickett construct an elaborate fantasy involving two unassuming and impartial social scientists under siege from industry-funded “merchants of doubt” who are trying to “give the impression that crucial areas of science affecting public policy are controversial, long after the implications of the science were quite clear.” (Why the tobacco industry would want to discredit The Spirit Level, of all books, can only be guessed at. One would think they had bigger fish to fry, but conspiracy theorists are able to overlook such logical conundrums.)

Wilkinson and Pickett’s combination of paranoia and self-aggrandisement falters for the simple reason that critics of The Spirit Level are not “free market fundamentalists” and they are certainly not all right-wing. The left-wing journalist Gerry Hassan has written about what he calls “the Fantasyland of The Spirit Level”:

Yet, it is almost impossible to compare these countries on equality; they are very different in their cultures, values and histories. Wilkinson and Pickett claim that ‘more equal societies almost always do better’—a universalist, sweeping statement—which cannot be substantiated by most of their data.... Part of the success of The Spirit Level is liberal guilt, part the retreat of the left, part wish-fulfilment and projection.

John Goldthorpe, Emeritus Professor of Sociology at Oxford University, said: “As I read through the book, I have to say that my reaction was one of increasing dismay.” Also a left-winger, Goldthorpe’s review of The Spirit Level can hardly be attributed to “free market fundamentalism.”

Wilkinson and Pickett [WP] have no time for nicely balanced judgements. They believe that the evidence they present shows beyond doubt that more equal societies ‘do better’, and they are also confident that they have the right explanation for why this is so... Their case is by no means so securely established as they try to make out... it has been called into question by other leading figures in the field—a fact that WP might have more fully acknowledged... WP’s inadequate, one-dimensional understanding of social stratification leads to major problems in their account of how the contextual effect is produced.

John Kay, Professor of Economics at London Business School, prefaced his review of The Spirit Level by saying that he was “sympathetic to its basic stance.” Nevertheless, he found it difficult to take the book’s methodology and conclusions seriously when he reviewed it in the Financial Times:

A larger source of irritation is the authors’ apparent belief that the application of regression methods to economic and social statistics is as novel to social science as it apparently is to medicine. The evidence presented in the book is mostly a series of scatter diagrams, with a regression line drawn through them. No data is provided on the estimated equations, or on relevant statistical tests. If you remove the bold lines from the diagram, the pattern of points mostly looks random, and the data dominated by a few outliers.

... An obvious conclusion is that there are many societies which perform well in terms of their own criteria. America, Sweden and Japan are just different from each other. Their achievements are not really commensurable. But Wilkinson and Pickett are not content with this relativist position.

Andrew Leigh describes himself as “about as anti-inequality an economist as you’ll find”. Formerly a Professor of Economics at the Australian National University, and now an Australian Labor Party politician, Leigh said of his own research into equality: “I had begun the project secretly hoping to find that inequality was bad, and wound up reluctantly reporting no such thing.” When asked his opinion of The Spirit Level, he wrote that “John Kay’s view in the FT comes closest to my own.”

“He didn't read the book thoroughly, obviously,” was Kate Pickett’s response when told about Kay’s review. Another person who didn’t read it properly was Christian Bjornskov, Professor of Economics at the University of Aarhus, who reviewed it in Population and Development Review:

The bottom line is that this is a well-written, stimulating polemic. It nevertheless suffers from the same problems as one-trick ponies: if the one trick does not impress you, the show is a failure. Wilkinson and Pickett’s trick simply does not hold up to empirical scrutiny. When assessing this book as a contribution to the debate on the “right” level of income differences in modern society, it is a highly interesting, sympathetic attempt at addressing some of the important problems of Western societies. Yet, when assessing this book from a scientific point of view, one is forced to conclude that it is a failure.

Robert Putnam, author of Bowling Alone and arguably America’s most prominent left-wing social scientist, has also expressed his discomfort with The Spirit Level. Putnam is quoted somewhat out of context by Wilkinson and Pickett to give the impression that Bowling Alone concludes that inequality erodes social capital. When asked his view of their work by journalist Shane Leavy, Putnam replied:

I have a mixed view about The Spirit Level. On the one hand, I believe that inequality is bad for society in many ways, just as that book argues. On the other hand, Pickett and Williamson’s [sic] work has been heavily (and I believe correctly) criticized as methodologically flawed. (For example, they don’t really show that the relationship between inequality and other bad things is causal, though they assume it is.) I hope that they (or others) will pursue that basic hypothesis in ways that are more scientifically persuasive.

These criticisms, and others like them, are manifestly not politically motivated. While there was no shortage of positive reviews from journalists, particularly on the left (The Guardian, The Independent, New Statesman, Socialist Review all provided rave reviews), many respected academics from both left and right have expressed serious concerns.

It suits Wilkinson and Pickett’s narrative to portray critics as being professional ‘merchants of doubt’ from the ‘far-right’. It helps to marginalise those who find fault with the book and deters their natural supporters from reading the critiques. It is, however, a fiction.

Questions have been raised about the bold conclusions of The Spirit Level because it is riddled with methodological flaws, selection bias, obvious cherry-picking, flawed reasoning and wishful thinking. Far from being the subject of a co-ordinated attack by nefarious vested interests, The Spirit Level has been criticised by everyone from Swedish economists, Irish psychologists and British sociologists—as well as numerous journalists, bloggers and reviewers around the world—for the simple reason that they have read it. It has been a best-seller and has transcended what Wilkinson calls the "left-wing ghetto". And amongst its large readership have been many rational people whose jaws dropped a little more at the turn of every page.

Ignoring crucial facts

2011-01-26T11:34:00.003Z

Any theory which explains the working of entire nations by looking at just one variable should strike us as being inherently questionable. We know that societies are moulded by a huge range of complex factors which come together over long periods of time. Some are accidents of circumstance, some are flukes of geography, history, climate or demography. Others are come about through the force of politics, religion or industry. However they come about, it is far from controversial to say that societies across the world are different for many reasons.

The Spirit Level relies on the premise that countries are fundamentally the same, with income inequality being the main variable that distinguishes them. Wilkinson and Pickett effectively disregard other variables such as absolute income, culture, history, ethnicity, geography, law, politics and climate. Throughout The Spirit Level, it is taken for granted that such factors have little or no bearing on their findings and so there is no attempt to adjust the figures for confounding factors, or even discuss them.

In the new postscript to the book, Wilkinson and Pickett group all these other variables together and dismiss them as “cultural differences” which, they say, have a negligible effect on their findings. To illustrate this, they say that Portugal and Spain perform very differently despite being culturally similar, while Japan and Sweden perform similarly despite being culturally different. This is not true. In most of the graphs, Portugal is actually closer to Spain than Japan is to Sweden.

More telling wold be a comparison between Japan (the most equal country) with Hong Kong and Singapore (the least equal countries). Despite the huge disparities in income inequality, these three societies perform much the same across nearly all criteria (imprisonment being the main exception). The obvious explanation is that these Asian societies are culturally similar.

Ignoring other variables and confounding factors would be a flaw in any study but when entire countries are under examination, this flaw becomes overwhelming. Tim Harford asked Pickett about their failure to consider other variables on More or Less. Her response was revealing. She and Wilkinson did not “believe” that factors other than inequality have an effect on a country's performance, so they didn’t go to the trouble of studying them.

TH: All of your studies are what are called bivariate analysis. In other words, they're all income inequality plotted against some other variable. Now, my understanding of best practice in social sciences is that you would always control for other variables. You would include 2, 3, 4, 5, 6 other variables and...

KP: Well, you wouldn't do that arbitrarily. You would do that if you believed those variables were potential alternative explanations of the relationship you're looking at.

TH: So, if I understand your statement correctly, you didn't include any multiple variable analyses because you just think that actually none of these variables are of interest—none of them are potential alternative explanations and you can just do the simple income inequality versus x analyses?

KP: That's right, but of course, again, other researchers have conducted studies that do control for more, where, as well as examining the effect of income inequality at the level of the whole society, people include individual's own levels of income or levels of education in those analyses and, again, those bear out our findings in relation to health.

TH: We come again to...you're basically rowing back from your analysis and saying...

KP: No. Indeed I'm not...

TH: "Don't look at our analysis, look at these other people because they support us."

KP: We believe that to control for individual income is actually over-controlling, so we would not consider that best practice.

Wilkinson and Pickett may not believe that individual income explains any of the differences between the countries they study, but while this is taken for granted in The Spirit Level, it is not unreasonable to take the view that social outcomes in Portugal, for example, would improve if its national income was the same as Norway’s (which would require a threefold increase in wealth).

Pickett is, however, correct in saying that other researchers have controlled for other variables. Shibuya et al., for example, controlled for income in their study of inequality in Japan and concluded:

After adjustment, individual income was more strongly associated with self-rated health than income inequality.

Fiscella and Franks controlled for income in their study of inequality in the USA and found:

In this nationally representative American sample, family income, but not community income inequality, independently predicts mortality. Previously reported ecological associations between income inequality and mortality may reflect confounding between individual family income and mortality.

Absolute income is a crucial confounding factor in studies of income inequality. Much of the debate about inequality and health revolves around the question of whether we can truly disentangle the effects of inequality from the effects of low income. Wilkinson and Pickett completely overlook this issue, and they never remark on the important observation that the poorest countries in their list (Portugal, Greece and New Zealand) all happen to be ‘less equal’. Nor do they comment on the fact that the perennially underachieving US states of Alabama, Louisiana and Mississippi also happen to be amongst the very poorest.

From the outset, income is assumed to have no role to play in The Spirit Level. Having announced that economic growth has “largely finished its work”, Wilkinson and Pickett simply assume that further wealth would not benefit the citizens of the countries they study (another glaring ecological fallacy, incidentally). It is assumed that absolute income has no effect because—as they show on page 12—life expectancy is no longer correlated with national income. But they do not test every criteria against income. If they did, they would find that several key outcomes are much more closely correlated with income than with inequality. This is true even of their cherished survey about trust, as the graphs below show. The first shows trust against national income; the second shows trust against income inequality.

Having breezily dismissed income as a third variable, Wilkinson and Pickett turn a blind eye to all other explanations for a country’s performance. Indeed, the only examples of them mentioning real-world differences occur when the ‘more equal’ countries fail to live up to their billing of ‘almost always’ doing better. For example, Wilkinson and Pickett are eager to explain Finland’s high homicide rate by pointing to its high level of gun-ownership while blaming the USA’s high homicide rate squarely on inequality. When Japan’s foreign aid contributions turn out to be “lower than expected”, they attribute it to the country’s “withdrawal from the international stage following the Second World War”. Britain’s “higher than expected” foreign aid spending, on the other hand, is explained by its “historical, colonial ties to many developing countries.” All of this may be true but Wilkinson and Pickett only seem aware of cultural and historical differences when it suits their argument.

In reality, of course, they know perfectly well that other variables have been shown to explain differences between countries far more convincingly than inequality. In their 2006 review of the literature, they identified 21 studies which “started off with supportive findings but then lost them as a result of the various control variables.” Income is one of those variables, but other recognised confounders include spending on health care, which has been found to explain the correlation between inequality and infant mortality:

The association of higher income inequality and higher infant mortality disappears when we control for health care expenditure. Our results indicate that the correlation between infant mortality and income inequality arises as income inequality is high in countries where public investment in health care is low.

And:

Although income inequality was positively associated with low birth weight and infant mortality, the association with infant mortality disappeared with the addition of sociodemographic covariates.

Levels of education have also been shown to explain correlations with inequality:

Multiple regression analysis of the 50 US states and District of Columbia for 1989-90 indicates that the relation between income inequality and age adjusted mortality is due to differences in high school educational attainment: education absorbs the income inequality effect and is a more powerful predictor of variation in mortality among US states.

Race is another important variable which is never adequately addressed in The Spirit Level. For example, one of the few studies looking at inequality and obesity acknowledged that:

Race is known to be significantly correlated with weight status, and is also associated with inequality... As race is a potential confounder of the relationship of interest, we stratify all analyses by race as well as sex.

The results of this study are worth repeating, since the they is ignored in The Spirit Level, in favour of Pickett’s own research:

We do not find a positive association between inequality and the likelihood of clinically relevant outcomes such as overweight and obesity. Indeed, the direction of association between inequality and weight status is generally negative among subgroups (though significant only for white women)... at least for non-Hispanic white women, living in a metropolitan area with greater income inequality is associated with lower BMI, lower odds for being overweight, and lower odds for being obese. [Emphasis in original]

Race has been shown time and again to be a major confounder in studies of inequality, to the extent that this one variable explains the entire correlation between inequality and poor health. This has been shown to be true in the USA:

In the results presented below, we show that, once we control for the fraction of the population that is black, there is no relationship in 1980 nor in 1990 between income inequality and mortality across either states or cities... That the estimated effects of income inequality are potentially confounded by the effects of race has been recognized since the ﬁrst papers on the topic. Blacks have higher mortality rates than whites and, on average have lower incomes, so that in places with a substantial black population, both income inequality and mortality, tend to be higher.

In Canada:

We replicate the finding that, net of the racial//ethnic composition of the population, the effects of income inequality are not significant.

And in New Zealand:

There is no convincing evidence of an association of income inequality within New Zealand with adult mortality. Previous ecological analyses within New Zealand suggesting an association of income inequality with mortality were confounded by ethnicity at the individual level.

The well-established importance of race as a confounding factor provided Wilkinson and Pickett with the excuse to land their lowest blow yet. In his book Beware False Prophets, Peter Saunders demonstrates that health and social outcomes are more closely correlated with the ethnic make-up of US states than with their levels of income inequality. For this, Wilkinson and Pickett accused him of a “seriously racist slur”. It was, they said, “racist because it implies the problem is inherently the people themselves rather than their socioeconomic position”.

It implied nothing of the sort. If Wilkinson and Pickett think it is racist to say that there are a host of cultural and historical reasons why blacks tend to do worse than whites in the USA, then there are plenty of black community leaders and black politicians who are racist. No serious discussion of modern-day America can ignore the legacy of slavery and segregation, as well as the more subtle forms of ongoing discrimination which continue to hold African-Americans back. Black Americans have, on average, higher rates of obesity, higher homicide rates and lower life expectancy. It should, therefore, be no surprise that states with large black populations tend to do worse under these criteria.

There is no doubt that racial inequality contributes to income inequality. Wilkinson and Pickett argue instead that income inequality is, at heart, the cause of racial inequality. Aside from being counterintuitive, this cannot be so because the correlation between race and health and social problems is stronger than the correlation with income inequality.

A significant clue lies in the pages of The Spirit Level itself. Wilkinson and Pickett’s discussion of mental health is a mass of contradictions. Having warned of the dangers of comparing apples and oranges, they proceed to do just that by cobbling together results from different studies which even they coyly admit are “not strictly comparable”. They attribute their failure to find a correlation between inequality and mental illness in the USA to the fact that mental illness does not have a social gradient, but this does not deter them from reporting a correlation between inequality and mental illness on an international level.

They then mention, almost in passing, that rates of mental illness are evenly distributed between different races. In light of their failure to find a correlation with mental illness in US states, this should have been a Eureka moment but, as Saunders writes:

[T]hey fail to draw the obvious conclusion from their failure to find a relationship with inequality, which is that they only get state-level correlations with income inequality when there are underlying correlations with race to generate them. [emphasis in the original].

Since there is no relationship between race and mental health, they cannot find a relationship with inequality. But since there are relationships between race and many other criteria, they find correlations with inequality. But those correlations are statistical associations resulting from Wilkinson and Pickett’s failure to adjust for race. They are not causal. Inequality is a symptom, not the cause.

Wilkinson and Pickett never adequately address the question of causality. There are many important confounders such as income, race, education and material deprivation which are correlated with inequality, but are not caused by inequality. Conversely, many social problems such as crime, drug abuse and gang formation do cause inequality because young people growing up in environments with gangs, drug abuse and high levels of crime are less likely to succeed in society. We can address those issues by fostering job creation or crime reduction in neighborhoods with social problems. But, by Wilkinson and Pickett’s reckoning, inequality is the cause of these problems and not a symptom. This leads us to the improbable conclusion that societal malaise can be alleviated by reducing income in the surrounding neighbourhoods.

There is plenty of research—all of it ignored in The Spirit Level—showing that inequality does not have an independent effect on health and social problems once other variables have been controlled for. It should go without saying that countries differ from one another in many ways that have nothing to do with income inequality. That these differences will lead to different outcomes should be equally obvious. Wilkinson and Pickett justify their refusal to consider other variables in the postscript, saying “including factors that are unrelated to inequality, or to any particular problem, would simply create unnecessary ‘noise’ and be methodologically incorrect.”

With this one sentence, every historical, cultural, religious, political, legal, geographical, climatic and demographic difference between whole societies is dismissed as ‘noise’. Again, they are assuming that these factors are “unrelated to inequality” without putting that assumption to the test. It is no wonder Wilkinson and Pickett fail to identify confounding factors. They were simply not looking for them.

Misrepresenting the evidence

2011-01-25T11:19:00.002Z

The Spirit Level’s endemic misrepresentation of the academic literature (see previous post) is made no less worrisome by its authors apparent inability to distinguish between a study which agrees with their hypothesis and one which merely mentions the word ‘inequality’. In response to criticism from Sanandaji et al. that their book focused on their own work while ignoring heavyweight academics, Wilkinson and Pickett wrote:

Other ‘heavyweight’ economists, including Nobel laureates, have also written about the significance of inequality for wellbeing and human capital formation.

As proof, they cited a study by James Heckman, winner of the Nobel Prize for Economic Sciences. Heckman is the co-author of a study titled ‘The Economics and Psychology of Inequality and Human Development’ but nothing in that paper—or in any of his work—implies support for Wilkinson and Picket’s inequality hypothesis. When Sanandaji asked Heckman about how he felt about having his study cited by the two social epidemiologists, he said bluntly: “This is a misrepresentation of my work.” As Sanandaji explains:

Note Wilkinson and Pickett’s choice of words. They write that Heckman has “written” about inequality and health, which is of course technically true. But what they don’t tell the readers is that while he has indeed written about these variables, he has not found any evidence supporting the claims of Wilkinson and Pickett. It is becoming increasingly tiresome to point this out, but Wilkinson and Pickett again and again engage in extraordinary acts of dishonesty.

Whether it be contemporary academics like James Heckman and Robert Putnam or—almost unbelievably—outspoken opponents of socialism such as Alexis de Tocqueville, Wilkinson and Pickett routinely cite the work of other scholars in a context which suggests that they agree with their hypothesis.

In some cases, the studies cited say the exact opposite of what Wilkinson and Pickett claim. As discussed in Chapter 4 of The Spirit Level Delusion, they attempt to explain the higher rate of suicide in more equal countries as a trade-off for a lower homicide rate. The problem with this is two-fold: less equal countries don’t have a higher homicide rate, and the countries studied in The Spirit Level show no evidence of an inverse relationship between homicide and suicide.

Responding to this on their website, Wilkinson and Pickett wrote: “In fact, there are several pieces of research which show that homicide rates are inversely related to suicide.” But the first study they cite as supporting evidence states quite clearly:

Our analysis indicates, overall, the correlation between homicide and suicide rates across all nations is very weak and statistically insignificant.

The shard of truth here is that homicide tends to be more common in very poor countries, while suicide tends to be more common in richer countries. But, as shown on page 82 of The Spirit Level Delusion, there is no correlation between homicide and suicide amongst the rich countries studied in The Spirit Level. And that, of course, is the relevant comparison when discussing Wilkinson and Pickett’s hypothesis.

Either Wilkinson and Pickett are relying on readers not checking their references or they genuinely believe that any study that mentions the word inequality in any context is supportive of their case. This was highlighted again when Kate Pickett was interviewed on BBC Radio 4’s More or Less programme.

It would be hard to find a less politically motivated radio show that More or Less—a programme dedicated to discussing the use and abuse of statistics in the modern media. Wisely deciding against passing judgement on such a voluminous topic in a half-hour magazine show, presenter Tim Harford opted for an interview with Pickett which, in its quiet way, was as devastating as anything written about The Spirit Level in 2010.

In this excerpt, Pickett uses the usual ‘consensus’ defence (see previous post), before being asked about a study she and Wilkinson reference in The Spirit Level to support their claim that “researchers at Harvard University showed that women's status was linked to state-level income inequality.”

KP: We wrote a book that's intended to be a synthesis of a very vast body of research. Not only our own, but those of other people... There is a consistent and robust and large body of evidence showing the same relationship.

TH: That's an interesting point that you make. Often, in response to critics, you have referred not to your own book, not to your own data but to other published research. I'd really like to focus on the research that's presented in your book. It's very easy to say there are 50 papers, there are 200 papers, that support our research but we don't really know how you've selected those papers.

KP: We actually have completed a systematic review of all of the studies of income inequality and health, and we reference that in our book. We do examine things systematically and certainly—when we are doing our own research, publishing in peer-reviewed journals—we have to be aware of all the literature in the field. But that doesn't mean that every paper in the field has good methods, comes to the right conclusion, studies the right thing.

TH: I absolutely agree. One of the papers that you refer to in support of your argument on women's empowerment and women's status which was published in 1999 by Kawachi and some other authors, you claim supports your findings on women's status and income inequality. I've looked at their abstract. It doesn't seem to attack that question at all. It's simply on another subject—a somewhat related subject but not on the subject of income inequality.

KP: They've definitely published and we may have inadvertently put the wrong reference into that document [laughing nervously]. But Kawachi and Kennedy have certainly published finding a relationship between income inequality and women's status. The paper is ‘Women's Status and the Health of Women and Men: a view from the States’ and it was published in Social Science and Medicine in 1999.

TH: That's the one I'm looking at.

The only claim in The Spirit Level that has generated anything approaching “a very vast body of research” is that related to health and inequality. Since their book was published, Wilkinson and Pickett have admitted that the correlation between life expectancy and inequality disappears when different measures of inequality are used. They have also said that “we accept that the inequality/health relationship is one of the weaker associations demonstrated in The Spirit Level.”

The best that can be said of the health-inequality hypothesis is that it remains unresolved and the scatter-plot presented on page 82 of The Spirit Level is unlikely to change that. Richard Wilkinson published a similar scatterplot in the British Medical Journal in 1992 and the peer-reviewed literature shows that he was accused of cherry-picking and data-mining at the time. It is no great surprise that he has received similar criticism now that he has filled an entire book with the same type of evidence.

But while there is an ongoing controversy amongst academics regarding the question of inequality and health, the bulk of The Spirit Level involves theories which have little or no support in the scientific literature. Wilkinson admitted as much in an interview with the magazine International Socialism:

"There are about 200 papers on health and inequality in lots of different settings, probably 40 or 50 looking at violence in relation to inequality, and very few looking at any of the other things in relation to inequality. In a way, the new work in the book is all these other variables—teenage births, mental illness, prison populations and so on—and the major contribution is bringing all of that into a picture that had previously been just health and violence."

What, then, is left of the idea that The Spirit Level is a “synthesis of a very vast body of research”? Wilkinson himself concedes that “very few” studies have looked at anything other than health in relation to inequality. Although Wilkinson and Pickett now portray themselves as standing on the shoulders of giants, in almost every important regard they stand alone.

The illusion of consensus

2011-01-24T13:49:00.003Z

A key plank in Wilkinson and Pickett’s defence of The Spirit Level is the notion that they are merely informing the general public about issues that have long since been agreed upon by the academic community. Since most people will never read any of the studies in the field, this has been largely successful as a public relations exercise, but it is a gross distortion.

It also represents something of a U-turn for the two social epidemiologists. Wilkinson and Pickett’s sudden insistence that they are reflecting the scientific consensus is at odds with the way they promoted their book when it was first released. In an interview with the couple in March 2009, the Guardian journalist reported that:

For a while, Wilkinson and Pickett wondered if the correlations were too good to be true. The links were so strong, they almost couldn't believe no one had spotted them before.

This could just about be excused as shoddy journalism were it not for Wilkinson and Pickett’s eagerness to take the credit for what they explicitly described as their “discoveries” in The Spirit Level itself. The book’s preface leaves the reader in little doubt that what they have discovered is genuinely new and exciting, hence the comparisons with Joseph Lister and Louis Pasteur. “The reason why the picture we present has not been put together until now is probably that much of the data has only become available in recent years,” they write, adding that “it could only have been a matter of time before someone came up with findings like ours.”

The truth of the matter, as discussed in Chapter 1 of The Spirit Level Delusion, is that there has been a large amount of research into the specific area of health and inequality spanning three decades. Richard Wilkinson has been a key figure in this field, but his views do not represent the consensus. Not could they, since there is emphatically no consensus. The only honest way to describe the state of the literature on health and inequality is to say it is mixed and conflicting. Researchers are broadly divided into three groups. There are those, like Wilkinson, who believe that there is a solid correlation between inequality and health outcomes and that this represents a causal link. There are those who believe there is a statistical correlation but that it is not causal, and there are those who believe there is no link at all.

Only the first of these positions is reflected in The Spirit Level, and the reader is given the false impression that academics have firmly established that inequality leads to poor health. Wilkinson and Pickett accuse their critics of not being familiar with the “extensive research literature”, but it is precisely because we are familiar with it that we know how grievously the pair misrepresent it in The Spirit Level. In the new postscript to the book (published November 2010), Wilkinson and Pickett say that “there are around 200 papers in peer-reviewed academic journals testing the relationship between income inequality and health”.

‘Testing’ is the key word here. There is no hint of how many of these studies have not found a relationship, nor of how many found a statistical relationship but concluded that it was not a causal. Their source for the ‘200 studies’ claim is, as so often in the book, one of their own papers. This article, from 2006, assessed 169 results from 155 studies on inequality and health (plus some other studies related to violence). By Wilkinson and Picket’s own reckoning, 88 of these were supportive of their theory (including 6 of their own studies) while 81 were either unsupportive or inconclusive.

Wilkinson and Pickett stress that many peer-reviewed articles have offered at least partial support to the relative income hypothesis. This is true—at least in the area of health—just as it is true that there are many peer-reviewed articles that beg to differ. Hence the long-running academic debate about inequality which The Spirit Level has done much to popularise but little to resolve. This debate has already been discussed in Chapter 1, but it might be useful to quote from some other researchers in the field:

All along, however, critical questions were being asked about the quality and interpretation of the data. In an early exchange, serious criticisms of the selection of countries, the quality of the data, and the lack of control for confounding in the BMJ paper of 1992 were only half countered. Although many aspects of this debate are still unresolved, it has recently become clear that the findings of that paper were an artifact of the selection of countries.

—British Medical Journal editorial, 2002

This paper extends previous studies by examining long time series for 12 of the world’s richest countries rather than one or two. Our ﬁndings are consistent with those of Deaton and Paxson (2001) and Lynch et al. (2004b), not with those of Wilkinson (1989, 1996) or Sen (1999). In our preferred speciﬁcations we find only small and statistically insigniﬁcant relationships between income inequality and mortality. This holds true regardless of whether we measure mortality using life expectancy at birth, infant mortality, homicide, or suicide.

—Leigh & Jencks, 2007

The study found limited evidence of an association between income inequality and worse self rated health in Britain, which was greatest among those with the lowest individual income levels. As regions with the highest income inequality were also the most urban, these findings may be attributable to characteristics of cities rather than income inequality. The variation in this association with the choice of income inequality measure also highlights the difficulty of studying income distributions using summary measures of income inequality.

—Weich et al., 2002

Estimates of the effect of income on health (the absolute income hypothesis) are likely to be biased. Tests of the relative income hypothesis are contaminated by the non-linearity of the individual health income relationship any association between income distribution and population health could be entirely due to it, rather than to any direct erect of relative income on individual health.... However, whilst Rodgers (1979) found that income distribution had a signiﬁcant negative association with life expectancy in almost all of his regression, we have found that the association is sometimes positive and sometimes negative and is never statistically signiﬁcant.... The ﬁndings should however be a further warning against using aggregate level studies as evidence for the relative deprivation hypothesis.

—Gravelle, 2000

Income inequality was not associated with health status... Household income, but not income inequality, appears to explain some of the differences in health status among Canadians.

McLeod et al., 2003

Significant differences in income inequality across regions and considerable changes in health are found across years, however, the panel data estimating regressions find no significant association between any of the measures of income inequality and self-reported health. Therefore, it would appear that the relative income hypothesis does not exist over time and does not exist within Britain.

Lindley & Lorgelly, 2005

Across Canadian health regions, health status in populations was a function of absolute income but not relative income.

—Vafaei et al., 2010

It can be ﬁrmly concluded, however, that there is insufﬁcient evidence supporting Wilkinson’s hypothesis once individual’s income and its differential impact are taken into account... There are substantial international variations in self-reported health, but they are not linked to the degree of income inequality... Wilkinson’s argument regarding contextual influences was based on a statistical artifact.

—Jen et al., 2009

Those with a healthy scepticism will have noticed that I have only quoted studies that support one side of the debate. It’s a slippery and misleading trick and it is exactly what Wilkinson and Pickett do throughout The Spirit Level. The difference is that I made it clear from the outset of this book that there are many conflicting studies. Readers of The Spirit Level would be hard-pressed to guess that there was any debate at all.

In their new postscript and in response to an article I co-wrote for the Wall Street Journal, Wilkinson and Pickett cite a 2009 review of self-reported health studies in the British Medical Journal which, they say, "leave[s] little room for doubt as to the veracity of these relationships [and] shows unequivocally that inequality is related to significantly higher mortality rates." With so many studies to chose from, it is reasonable to expect Wilkinson and Pickett to cite one which strongly supports their position. But while the BMJ study is more supportive than most, it can hardly be called unequivocal. It begins by noting that:

Empirical studies have attempted to link income inequality with poor health, but recent systematic reviews have failed to reach a consensus because of mixed findings.

And concludes:

The results suggest a modest adverse effect of income inequality on health, although the population impact might be larger if the association is truly causal... The findings need to be interpreted with caution given the heterogeneity between studies.

It says much how about how weak the alleged ‘consensus’ is that the study Wilkinson and Pickett use as killer proof that inequality causes poor health did not find a strong relationship and acknowledged that the “modest” association was weak enough to imply a lack of causality. If this is “unequivocal” evidence, what is the rest like?

Other researchers who have reviewed the evidence have not been so generous. For example:

Only individual-level studies have the potential to discriminate between most of the advanced hypotheses. The relevant individual-level studies to date, all on U.S. population data, provide strong support for the “absolute-income hypothesis,” no support for the “relative-income hypothesis,” and little or no support for the “income-inequality hypothesis.”

—Wagstaff & Doorslaer ('Inequality and Health: What does the literature tell us?')

The undeniable absence of a strong or consistent relationship between inequality and health stands in stark contrast to previous claims.... Contrary to the claims of previous researchers, there is no strong empirical support for the contention that inequality is a determinant of population health, let alone one of the most important determinants.

—Mellor and Milyo ('Reexamining the Evidence of an Ecological Association between Income Inequality and Health')

This article reviews 98 aggregate and multilevel studies examining the associations between income inequality and health. Overall, there seems to be little support for the idea that income inequality is a major, generalizable determinant of population health differences within or between rich countries.

—Lynch, ('Is income inequality a determinant of population health?')

Much of the literature, both theoretical and empirical, needs to be treated skeptically, if only because of the low quality of much of the data on income inequality. Although there are many remaining puzzles, I conclude that there is no direct link from income inequality to mortality; individuals are no more likely to die or to report that they are in poor health if they live in places with a more unequal distribution of income.

—Deaton ('Health, Inequality, and Economic Development')

The last quoted paragraph comes from a review of the literature conducted by Prof. Angus Deaton of Princeton University, one of the world’s most respected economists, whose summary of the evidence has twice as many citations in the scientific literature as Wilkinson and Pickett’s 2006 paper. Despite this, the postscript to The Spirit Level finds Wilkinson and Pickett stating that “it is now extremely difficult to argue credibly that these relationships don’t exist. Indeed, those who do so are almost always those who are making political attacks rather than any kind of academic criticism.” This statement goes beyond the merely misleading and enters the realms of flagrant dishonesty. In 2009, The Oxford Handbook of Economic Inequality evaluated the evidence for the inequality-health hypothesis and concluded:

The preponderance of evidence suggests that the relationship between income inequality and health is either non-existent or too fragile to show up in a robustly estimated panel specification. The best cross-national studies now uniformly fail to find a statistically reliable relationship between economic inequality and longevity.

Having to resort to the appeal to authority is regrettable, but since Wilkinson and Pickett are so eager to bill themselves as “epidemiologists with decades of experience in analysing the social determinants of ill health”, it behooves me to be said that each chapter of The Oxford Handbook of Economic Inequality is written by a team of distinguished professors who are regarded as international experts in their field. The implication that the work of these eminent scholars is “ill-founded and politically motivated criticism” is risible. Unlike Wilkinson and Pickett, none of these academics have formed any political pressure groups and do not have a long history of demanding radical wealth redistribution.

As Sanandaji et al., have noted, the idea that Wilkinson and Pickett took their message directly to the public only after winning the academic debate is one of The Spirit Level’s most enduring myths:

The general public—the target audience for The Spirit Level—cannot be expected to be aware of the state of research in the field. Wilkinson and Pickett exploit the trust of their readers and give them the impression that their claims represent consensus science, when the opposite is closer to the truth.

Wilkinson and Pickett totally misrepresent the literature on inequality and health in The Spirit Level. They build the illusion of consensus around the one criterion that has generated substantial academic study (health) without ever acknowledging that the inequality-health hypothesis remains highly controversial and that Wilkinson's attempts to 'prove' it have attracted much criticism in the peer-reviewed literature spanning two decades.

Having given a distorted and one-sided account of the research into health and inequality, they then lead the reader to believe that there is also a "vast literature" supporting their claims about other criteria. In fact, the amount of published research into these other criteria range from scant (eg. infant mortality, obesity, teen births) to none at all (eg. foreign aid, recycling, innovation). Wilkinson and Pickett's misrepresentation of the work of other academics will be the subject of the next post.

The Spirit Level has been debunked. More or less.

2010-08-30T21:11:00.001+01:00

The BBC Radio 4 show More or Less looks at the facts behind well publicised statistics. The show is presented by the author of The Undercover Economist, Tim Harford and, as a regular listener, I was intrigued to hear that the first show of the new series promised to 'decode The Spirit Level debate'. For a show dedicated to debunking junk statistics it was obvious subject matter, but I wondered how Harford could 'decode' such a voluminous topic over the airwaves in one show.

In the end, he didn't need to. From the outset, Harford admitted there were too many competing claims to fit into a magazine show, and instead interviewed The Spirit Level's co-author Kate Pickett, who did more damage to the reputation of The Spirit Level in the space of ten minutes than any number of supposed "idea wreckers".

The interview (listen here for the next couple of days, or subscribe to the podcast) is essential listening if you've been following the controversy, as Pickett struggles to answer some fair and simple questions. Strangely enough, Wilkinson and Pickett's Equality Trust website—which is normally so quick to let people know when The Spirit Level has been mentioned in the media—have yet to post a link to this interview. And since the audio file won't be available for much longer, I've transcribed some of the key moments for posterity...

Falling back on other people's research

Wilkinson and Pickett's first line of defence is to claim that there are 100s of peer-reviewed studies which support their conclusion. As I have said before, this is just not true. Most of the studies they reference in The Spirit Level do not even mention income inequality.

In the More or Less interview, Kate Pickett once again claimed there was a "vast body of research" behind The Spirit Level. Tim Harford picked her up on it...

KP: We wrote a book that's intended to be a synthesis of a very vast body of research. Not only our own, but those of other people... There is a consistent and robust and large body of evidence showing the same relationship.

TH: That's an interesting point that you make. Often, in response to critics, you have referred not to your own book, not to your own data but to other published research. I'd really like to focus on the research that's presented in your book. It's very easy to say there are 50 papers, there are 200 papers, that support our research but we don't really know how you've selected those papers.

KP: We actually have completed a systematic review of all of the studies of income inequality and health, and we reference that in our book. We do examine things systematically and certainly—when we are doing our own research, publishing in peer-reviewed journals—we have to be aware of all the literature in the field. But that doesn't mean that every paper in the field has good methods, comes to the right conclusion, studies the right thing.

TH: I absolutely agree. One of the papers that you refer to in support of your argument on women's empowerment and women's status which was published in 1999 by Kawachi and some other authors, you claim supports your findings on women's status and income inequality. I've looked at their abstract. It doesn't seem to attack that question at all. It's simply on another subject—a somewhat related subject but not on the subject of income inequality.

KP: They've definitely published and we may have inadvertently put the wrong reference into that document [laughing nervously]. But Kawachi and Kennedy have certainly published finding a relationship between income inequality and women's status. The paper is Women's Status and the Health of Women and Men: a view from the States and it was published in Social Science and Medicine in 1999.

TH: That's the one I'm looking at.

Note: On page 58 of The Spirit Level, it states: "Researchers at Harvard University showed that women's status was linked to state-level income inequality. (36)"

Reference 36 is the Kawachi study ('Women's status and the health of women and men: a view from the States', 1999). As its title suggests, this study compared women's status with health, not with inequality. Indeed, the authors found a correlation between women's status and health even after controlling for income inequality.

Failure to look at other variables

The Spirit Level relies on the conceit that countries are fundamentally the same, with income inequality being the main variable that distinguishes them. This allows Wilkinson and Pickett to disregard other variables such as income, culture, history, demography, ethnicity, geography, law, politics and climate. Ignoring other variables and confounding factors would be a flaw in any study—as Harford points out, it breaks a basic rule of epidemiology—but when entire countries are being studied, this flaw becomes overwhelming. Pickett's response is revealing: she and Wilkinson do not "believe" that factors other than income inequality have an effect on a country's performance, so they don't bother looking at them.

TH: All of your studies are what are called bivariate analysis. In other words, they're all income inequality plotted against some other variable. Now, my understanding of best practice in social sciences is that you would always control for other variables. You would include 2, 3, 4, 5, 6 other variables and...

KP: Well, you wouldn't do that arbitrarily. You would do that if you believed those variables were potential alternative explanations of the relationship you're looking at.

TH: So, if I understand your statement correctly, you didn't include any multiple variable analysis because you just think that actually none of these variables are of interest—none of them are potential alternative explanations and you can just do the simple income inequality versus x analyses?

KP: That's right, but of course, again, other researchers have conducted studies that do control for more, where, as well as examining the effect of income inequality at the level of the whole society, people include individual's own levels of income or levels of education in those analyses and, again, those bear out our findings in relation to health.

TH: We come again to...you're basically rowing back from your analysis and saying...

KP: No. Indeed I'm not...

TH: "Don't look at our analysis, look at these other people because they support us."

KP: We believe that to control for individual income is actually over-controlling, so we would not consider that best practice.

Academic criticism

Although well received by some journalists and politicians, The Spirit Level has received a much cooler reaction from academics. One of the few serious academics to have reviewed the book was John Kay, Professor of Economics at London Business School and former Director of Institute of Fiscal Studies. Pickett's response to Kay's review speaks volumes...

TH: When John Kay reviewed your book in the Financial Times —and I believe John Kay would be broadly sympathetic to your idea that egalitarianism is important—he wrote: "The evidence presented in the book is mostly a series of scatter diagrams with a regression line drawn through them. No data is provided on the estimated equations, or on relevant statistical tests. If you remove the bold lines from the diagram, the pattern of points mostly looks random, and the data dominated by a few outliers." Do you think that's fair?

KP: No, I don't think it's fair. [Testily] He didn't read the book thoroughly, obviously.

Outlandish claims

In the last chapter of The Spirit Level, Wilkinson and Pickett make some extraordinary claims about what could happen if Britain reduced income inequality to Scandinavian levels. These include: teen births falling to a third of current rates, mental illness being halved, life expectancy rising by a year and the murder rate falling by three-quarters. Harford asks her about the last of these predictions.

TH: Clearly your book is a systematical analysis and partly also a political book. You have a political case to make—there's nothing wrong with that. You have public policy actions that you would like to see taken. But do you think you may have overstated some of those? Let me give you an example. On page 268 of you book—towards the conclusion—you say that if Britain became as equal as Japan, Norway, Sweden and Finland, homicide rates could fall by 75%. But as I'm sure you've had pointed out to you by now, the UK's homicide rate is already below the average of those four countries.

KP: It's not actually. It's been pointed out that it's below Sweden. It's not below the average of those countries. Those claims [ie. in The Spirit Level], they're based on regression models and of course they're only as good as they're model they're based on.

TH: [Incredulously] But.. sorry... but you've made that claim!

KP: Yes, yes, we do...

TH: And you stand by it?

KP: Yes. That Britain would become a much healthier and more socially better functioning place if it were more equal.

TH: You said that if Britain became as equal as these four countries, homicide rates could fall by 75%. Do you not feel that's really overstating the case, or do you stand by that?

KP: That's based on the model. I mean, I think we could try it and see.

[end of interview]

TH: Kate Pickett, co-author of The Spirit Level. We did go to her Equality Trust website, by the way, and downloaded the data on homicide rates in the UK and in the relevant four countries and it does seem that I was right to say that the UK's homicide rate is already below the average of those four countries. You're listening to More or Less...

Today's report in The Guardian

2010-08-14T08:01:00.000+01:00

Today's report in The Guardian will no doubt draw the usual hate and bile from people who have no intention of reading my book. Still, a few quick points...

Nobody asked me or paid me to write this book. I never set out write a critique of another book. While I was researching a completely different topic, I bought and read The Spirit Level because, as I said to The Guardian, it was "influential and informing debate." Those are the kinds of books I like to read, whether from left or right. When I started fact-checking The Spirit Level I realised that it was too big a subject to squeeze into an article or blog post and The Spirit Level Delusion was born.

When Dr Patrick Basham kindly offered to write the preface for the book, I published it in association with the Democracy Institute, of which he is the director. Had I known this would leave the book open to accusations of being written by a "wrecker" from a "rightwing thinktank" I wouldn't have bothered. You live and learn.

I knew when I wrote it that the dogmatic right wouldn't be interested because they wouldn't have read The Spirit Level. I knew the dogmatic left wouldn't be interested because they'd put their fingers in their ears if anyone raised difficult questions about such a politically useful text. But I also knew that there would be some people in between who had enquiring minds and a genuine interest in the issues. Perhaps I overestimated how many fell into that camp.

The Guardian quoted a few words from a twenty minute interview. No complaints, that's the way it goes...

He [Snowdon] does not believe that The Spirit Level's claim that the psychological effects on society of income inequality are so great to cause widespread social ills. "I don't think people outside the intelligensia worry about inequality," Snowdon said. "The working class don't worry about how much Wayne Rooney is earning."

It's a crude example, but it serves to illustrate one of the fundamental problems with The Spirit Level. It cannot be stressed often enough that Wilkinson and Pickett's hypothesis rests on the psychological (or 'psychosocial') effects of living in a less equal society, not the material effects of poverty.

When people say that they find The Spirit Level's conclusions to be 'intuitively' true, or that they appeal to 'common sense', I wonder whether they fully appreciate that Wilkinson and Pickett are not blaming poverty, low income or low living standards per se. They are talking about something much less tangible—a sense, a feeling, a response—to other people's wealth. As someone who happens to be in the bottom 20% of earners myself, I don't personally feel traumatised by the existence of the super-rich. Perhaps that's just me, but there is also very little empirical evidence that the psychological response to inequality has a significant effect on people's day-to-day lives.

Wilkinson and Pickett would disagree, but the (left-wing) economist JK Galbraith understood this back in 1958 when he wrote The Affluent Society:

Envy almost certainly operates efficiently only as regards near neighbours. It’s not directed towards the distant rich.

In a later preface to The Affluent Society, Galbraith returned to the issue of inequality, making it clear that so long as people's own living standards were improving, they are not troubled by the thought of other people becoming still richer:

When, as suggested in this book, men and women are employed and at continuously improving wages or salaries, they are not greatly concerned that others, with whatever justification or absence of justification, have more, even greatly more.

More recently, in Status Syndrome, the (left-wing) epidemiologist, Michael Marmot discussed the stubborn refusal of ordinary Americans to become less happy even as their country became less equal. He made a telling comment about who is really 'stressed' by income inequality:

Changes in income inequality did not affect happiness levels of the poor. The subgroup of the population whose happiness declined when income inequality increased, were richer people who described themselves as on the left politically.

I discuss this issue in more detail in the later chapters of the book.

No doubt there is resentment at some of the grotesque disparities of wealth that exist (and have always existed), but that resentment would have to be truly monumental for it to be the main driver of an entire country's performance across so many criteria. Very few variables—let alone psychological variables—show up in aggregate data from whole nations. The psychosocial effect of income inequality is not one of them, and Wilkinson and Pickett have to perform all sorts of twists and turns to make their case to the contrary. At best, The Spirit Level gives a cock-eyed view of the way the world is.

The case for greater income equality remains an ethical, moral and political issue. It cannot be 'proved' by social science.

My response to Wilkinson and Pickett's answers to my 20 Questions is here .

Some of the graphs from The Spirit Level Delusion are here.

Links to other sites discussing the debate over The Spirit Level can be found on the right-hand side of the page.

Reply to Prospect magazine article

2010-08-11T03:27:00.000+01:00

This is my reply to an article in Prospect by Richard Wilkinson and Kate Pickett. That article can be read here. The article that inspired it is here.

I’m pleased to be able to agree with Wilkinson and Pickett (W & P) on one point. I’m not a public health researcher and was surprised to be described as such. That, sadly, is where agreement ends.

Wilkinson and Pickett once again imply that they are merely the messengers of a scientific consensus and that there are 100s of peer-reviewed studies saying the same thing. Can we please put this one to bed? Even if quantity was a substitute for quality, the argument does not apply here. There is a large body of conflicting research about health and inequality and a smaller body of research studying violence and inequality. Both are hotly debated, not least because it is very difficult to isolate the effects of income inequality from the effects of low income.

Beyond this, Wilkinson and Pickett are out on their own, making claims that have virtually no support in the scientific literature. In contrast to what he says in the third paragraph of this rejoinder, Wilkinson recently told the magazine International Socialism:

"There are about 200 papers on health and inequality in lots of different settings, probably 40 or 50 looking at violence in relation to inequality, and very few looking at any of the other things in relation to inequality. In a way, the new work in the book is all these other variables—teenage births, mental illness, prison populations and so on—and the major contribution is bringing all of that into a picture that had previously been just health and violence."

W & P confuse making assumptions based on other people’s research with having those people actually agree with them. For example, they cite studies that quite reasonably associate overeating with stress, but it does not follow that obesity rates vary internationally because the population is stressed about inequality. At best, this is speculation.

W & P continue to cite perfectly sound studies showing there to be social gradients to health and social problems as evidence that inequality affects a nation’s overall performance. It does not. These are completely different issues.

Which leaves us with W & P’s own evidence, which relies on comparing whole countries, a notoriously unreliable method which allows unlimited scope for misinterpretation. The criticisms recently made of this evidence by myself and others closely echo criticisms made in peer-reviewed journals when Wilkinson used similar methods in the past. They also echo criticisms made by the few serious academics who have reviewed The Spirit Level.

Anyone who believes that W & P “never pick and choose data points to suit our argument” should compare references 2 and 6 in The Spirit Level (p. 271) and ask themselves why one year’s data were used for one graph and another year’s data used for the next. Anyone who believes that they use “the same measures of inequality” should turn to page 224 and ask why a dramatically different measure of inequality was preferred when working hours were studied (clue: see how it looks when we use W & P’s more usual measure of inequality). Anyone believing that they have not “picked problems to suit our argument” might ask why they show how much overseas aid is given by a country’s government, but do not show how much is given privately (there is no correlation with inequality when the two are combined).

As for always using the same group of countries, one of The Spirit Level’s most serious flaws is the baffling assumption that “rich market societies” come in batches of 50. If there is to be a cut-off point beyond which economic growth has “largely finished its work”, it should be based on something more than a round number. Without a convincing justification for why places like the Czech Republic and South Korea – let alone Hong Kong – cannot be considered rich market societies, we must ask the next question: why do these societies conspicuously fail to fit Wilkinson and Pickett’s theory? The United Nations classes these countries as being of “very high human development”, why doesn’t The Spirit Level?

I hope that readers will take the time to look at these issues themselves, but, if not, they should at least take a deep breath and ask themselves which is more plausible – a theory that seeks to explain the workings of whole societies by reference to a single factor, or one that says that a country’s performance is the result of countless historical, geographical, political, legal, demographic and economic factors, of which the public’s response to income inequality may or may not be one.

Are people in 'more equal' countries more likely to vote?

2010-07-29T13:01:00.000+01:00

In the latest edition of The Spirit Level, Wilkinson and Pickett put forward the idea that voter turn-out is higher in "more equal" countries.

There is evidence from societies where voting is not compulsory (as it is for instance in Australia) that voter turn-out may be lower in more unequal countries. Whether or not this reflects a greater separation of interests and an increasing sense of 'us and them' between people at opposite ends of the social ladder, it certainly suggests that too much inequality is a threat to democracy.

The Spirit Level, p. 295 (revised edition)

The reference given to support this claim is cited as 'B. Geysa, 'Explaining voter turnout: A review of aggregate-level research'. This study is available online. Aside from getting the name of the author wrong (it's Geys, not Geysa), Wilkinson and Pickett totally misrepresent the study's findings. The word 'inequality' appears just three times in this 27 page review and although it briefly addresses the question of whether inequality might reduce voting turn-out, it clearly concludes that most studies have shown that it doesn't. At no point does it even vaguely imply that "voter turn-out may be lower in more unequal countries", let alone that this represents a "threat to democracy".

Wilkinson and Pickett do not present a graph of their own as evidence, but thanks to recently published OECD data on voter turn-out, we can put the hypothesis to the test. The graph below shows all rich OECD countries, excluding tax havens (as per The Spirit Level) and Australia (where voting is compulsory).

It would be hard to produce a straighter line. Even with a spirit level.

Fact-checking The Spirit Level debate

2010-07-23T17:03:00.000+01:00

Thanks to all who organised and attended the debate at the Royal Society of Arts on 22nd July. Due to the structure of the event, Peter Saunders and myself did not get the chance to reply to Wilkinson and Pickett's presentation but, although I haven't yet listened back to the debate (I'll post the video link when it is available), there are a few basic factual errors that need clearing up...

1. Trust

In response to my claim that the correlation between trust and inequality depends entirely on the Scandinavian countries, Pickett presented a graph which showed the same data (from The Spirit Level) but with the Scandinavian countries excluded. A correlation remained, albeit weaker.

This is true, but the two critical problems with their graph on trust remain: (1) As with all Spirit Level graphs, it excludes several wealthy countries; (2) it relies on data from the 1990s which has been superseded by the 2000s data (which is used in The Spirit Level Delusion). When the most recent data is used there is clearly no correlation between trust and inequality.

Source: World Values Survey

2. Happiness

Richard Wilkinson dismissed the evidence showing that happiness is not correlated with income inequality—but is (positively) correlated with income—by saying that happiness does not have a social gradient.

This is not true. Happiness certainly does have a social gradient. One of the best known demonstrations of this can be found in a paper by Robert Easterlin from 1974. It clearly shows happiness rising in line with income.

This particular article gave rise to the so-called 'Easterlin Paradox' and is one of the most famous papers in economics. It is certainly the most famous study in the field of 'happiness studies', and as such it is hard to believe that Wilkinson can be unaware of it.

Source: Does Economic Growth Improve the Human Lot? Some Empirical Evidence, Robert Easterlin, 1974

3. Health

In response to our evidence showing no relationship between inequality and life expectancy, Pickett referred to a 2009 study from the British Medical Journal. Wilkinson and Pickett also cited this study in their response to Peter Saunders and in their response to a recent critique I co-authored in the Wall Street Journal. In the latter, they said that the BMJ study "shows unequivocally that inequality is related to significantly higher mortality rates."

In fact, the BMJ study concludes that:

The results suggest a modest adverse effect of income inequality on health, although the population impact might be larger if the association is truly causal... The findings need to be interpreted with caution given the heterogeneity between studies.

Unequivocal?

4. The Spirit Level was written in 2007?

Kate Pickett referred to one of my 20 Questions, which reads:

Why do you say that the USA’s decline in homicide ended in 2005 when 2008 saw the lowest number of homicides since 1965? As you must know, America's murder rate has halved in the last two decades despite rising inequality.

All of which is true. Wilkinson and Pickett claim that the US homicide rate "started to rise again" in 2005 (p. 142). In fact, the murder rate fell in 2007 and 2008 and is now at its lowest rate since 1965.

During the debate, Pickett explained that there was a simple reason for them ignoring the ongoing decline in the US homicide rate—their book was written in 2007! That got a good laugh, but it is not true. As can be seen from the references at the end of The Spirit Level, they were still writing—and finding new sources—well into 2008.

For example:

(95) S. Bezruchkra et al., 'Income economic equality and health: the case of postwar Japan', American Journal of Public Health, (February 2008)

(298) K. Pickett & R. Wilkinson, 'People like us: ethnic group density on health', Ethnicity and Health, (September 2008)

(379) W. Hutton, 'Let's get rid of our silly fears of public ownership', The Observer, (April 2008)

Clearly there was time to acknowledge the US homicide rate in 2007, if not 2008.

5. Inequality in Japan

During the Q & A session, I mentioned that there are questions over how equal the distribution of wealth in Japan really is. I pointed out that Gini figures from the OECD show Japan to be on a par with Spain and Portugal (this was a mistake on my part—I meant to say Spain and Greece). Pickett responded by saying that these figures are for Gini before tax.

This, again, is not true. The OECD provides inequality data both before and after tax. The most recent data, from the mid-2000s, show:

Japan (before tax): 0.44

Japan (after tax): 0.32

Spain (before tax): 0.41

Spain (after tax): 0.32

Greece (before tax): 0.43

Greece (after tax): 0.32

Sweden (before tax): 0.43

Sweden (after tax): 0.23

As the OECD states in a 2006 article:

The Gini coefficient measure has risen significantly since the mid 1980s from well below to slightly above the OECD average and the rate of relative poverty in Japan is now one of the highest in the OECD area.

I have no firm view on which of the two sources (UN or OECD) have the most realistic figure for Japan, but as a point of fact the OECD figures I mentioned were after tax.

Source: OECD

The Spirit Level, the Policy Exchange and the race card

2010-07-23T13:09:00.000+01:00

It was enough to suggest a vast right-wing conspiracy. Last week, three debunkings of the left’s new favourite text The Spirit Level appeared in as many days—first from the TaxPayers’ Alliance, then from Policy Exchange and then in the Wall Street Journal. This coincidence (I assure you it was a coincidence) was enough to rouse The Spirit Level’s authors—social epidemiologists Richard Wilkinson and Kate Pickett—into responding, to the Policy Exchange’s rebuttal at least. Disappointingly, this response was heavy on name calling and light on substantive arguments.

Wilkinson and Pickett insisted that their book was the result of “decades of research”. True enough. Richard Wilkinson has doggedly pursued the theory that “unequal societies are almost always unhealthy societies” for the last 35 years. During that time, life expectancy has risen rapidly, despite growing inequality, leaving ultra-egalitarian Denmark with the lowest life expectancy of any country studied in The Spirit Level. That none of this has swayed Wilkinson from his hypothesis is a tribute to his indefatigability, but stamina alone is not enough. People have spent their lives on more quixotic endeavours than Wilkinson, but that should not necessarily recommend them to us.

Wilkinson and Pickett stress that many peer-reviewed articles have offered at least partial support the relative income hypothesis. This is also true—albeit only in the area of health—even if Wilkinson has written a large number of them himself, but there are also plenty of peer-reviewed articles that beg to differ. Hence the long-running academic debate about inequality which The Spirit Level has done much to popularise but little to resolve.

Amongst that large body of scientific literature, there have been several suggestions of selection bias on Wilkinson’s part (that’s ‘cherry-picking’ to you and me) which have been echoed recently with regards to the The Spirit Level. Wilkinson and Pickett throw the same accusation at Peter Saunders, the author of the Policy Exchange critique, saying that he selectively removed a number of countries from his analysis. This would be a potent criticism had Saunders picked the most useful subset of countries and used them throughout. In fact, he only occasionally excludes a handful of outliers to show that Wilkinson and Pickett’s regression lines are being dragged this way and that by a few special cases, thereby creating the illusion of a sloping gradient where none exists.

It is valid, indeed crucial, to demonstrate this point. Take their graph on obesity, for example. Even the casual reader can see that the line goes upwards as a result of fat Americans and skinny Japanese. There is a conspicuous lack of a dose-response relationship when it comes to the other countries, but note the absence of Singapore and Hong Kong in this graph, both wealthy societies which marry extreme inequality with low rates of obesity (and low rates of most other health and social problems). Wilkinson and Pickett are no strangers to “arbitrarily cutting out certain countries” themselves.

Conversely, Wilkinson and Pickett accuse Saunders of including too many countries (he shows 44 to Wilkinson and Pickett’s 23). This is a view I have a little more sympathy with. Places like Russia and Chile clearly have absolute poverty in a way that France and Norway do not. Since Wilkinson and Pickett accept that wealth improves countries up to a point, it could certainly be said that several of the nations included in Saunder’s analysis have not reached that point. However, as both The Spirit Level Delusion and the TPA report show, one need only to include countries which are as wealthy or wealthier than Portugal to show that there is no relationship between inequality and most health and social problems. Wilkinson and Pickett have yet to justify their decision to exclude places like South Korea, the Czech Republic, Slovenia and Hong Kong.

Wilkinson and Pickett then aim a blow below the midriff when they accuse the Policy Exchange of being “from the political far right” and accuse Saunders of a “seriously racist slur” for showing the tendency of US states with large African-American populations to have the most social and health problems. The correlation with ethnicity is strong—much stronger than the correlation with inequality—but Wilkinson and Pickett dismiss it as “racist because it implies the problem is inherently the people themselves rather than their socioeconomic position”.

If Wilkinson and Pickett think it is racist to say that there are a host of cultural and historical reasons why blacks tend to do worse than whites in the USA, then there are plenty of black community leaders and black politicians who are racist. No serious discussion of modern-day America can ignore the legacy of slavery and segregation, as well as the more subtle forms of ongoing discrimination which continue to hold African-Americans back. There is no doubt that these factors contribute to income inequality, but to say they are caused by inequality is highly questionable.

The reasons why the black homicide rate is much higher, and black life expectancy much lower, than the corresponding rates for white Americans are many and varied but in The Spirit Level, they are—as ever—reduced to symptoms of inequality. This will not do. Income, inequality and ethnicity are so closely intertwined in the United States that it is difficult to see where one stops and the other starts, but Saunders argues persuasively that inequality is not the main driver.

A significant clue lies in the pages of The Spirit Level itself. Wilkinson and Pickett note with surprise that they can find no association between inequality and poor mental health (p68-69) and then mention, almost in passing, that rates of mental illness are evenly distributed between different races. This should have been a Eureka moment but, as Saunders writes, “they fail to draw the obvious conclusion from their failure to find a relationship with inequality, which is that they only get state-level correlations with income inequality when there are underlying correlations with race to generate them” [emphasis in original]. Inequality is a symptom, not the cause.

This highlights one of the main problems with The Spirit Level. The myopic obsession with income inequality blinds the eye to the countless cultural, political, historical and demographic reasons why countries are as they are. Wilkinson and Pickett’s hypothesis requires one to believe that these are all rooted in inequality, but taking each in turn we can see how implausible that is. Their ‘theory of everything’, like all grand unifying theories, makes an extraordinary claim and requires extraordinary evidence. As was repeatedly demonstrated last week, the evidence provided in The Spirit Level withers under the light of serious scrutiny. Crying ‘racist’ will not make it more robust.

[This article was first published by the TPA on 16.07.10]

[Peter Saunders has responded to Wilkinson and Pickett's attack on his website]

[Tino Sanandaji—one of the authors of the WSJ article—makes some additional comments on his blog]

Correlation coefficients and p-values

2010-07-22T19:33:00.000+01:00

The original edition of The Spirit Level did not show correlation coefficients or p-values for any of the graphs, but when I wrote The Spirit Level Delusion, I included r-squared coefficients to show the strength of the associations.

Later editions of The Spirit Level include an appendix which shows Pearson Correlation Coefficients and two-sided p-values. As the Pearson coefficient shows a different figure than the r-squared, I have included the Pearson coefficients and the two-sided p-values for The Spirit Level Delusion graphs below for anybody who should want to compare them.

The first number is the correlation coefficient (the strength of the correlation). The figure in brackets is the p-value (the confidence that the correlation has not been caused by chance). Both numbers go from 0.00 to 1.00. For the first figure, the higher the number, the stronger the correlation. For the latter, lower numbers represent stronger associations. Statistical significance is usually represented by a p-value of at least 0.05, with 0.01 or less being preferred.

Life expectancy (UN 2004): -0.4515 (0.03)

Life expectancy (UN 2006): 0.16 (0.42)

Life expectancy (UN 2009): 0.22 (0.27)

Obesity: 0.01 (0.96)

Smoking: -0.31 (0.11)

Alcohol: -0.25 (0.21)

Infant mortality: 0.13 (0.51)

Trust: -0.29 (0.13)

Teen births: 0.32 (0.10)

Happiness: 0.05 (0.81)

Homicide: 0.30 (0.12)

Recycling/suicide: 0.64 (0.04)

Prison: 0.59 (<0.01)

Crime: -0.15 (0.45)

Victim of crime: -0.344 (0.21)

Recycling: -0.739 (<0.01)

Charity: 0.40 (0.25)

Foreign aid: 0.527 (0.01)

Single parents: -0.06 (0.285)

Suicide: -0.475 (0.01)

Unemployment: 0.033 (0.88)

Community life: 0.54 (0.03)

Alcohol/divorce: 0.35 (0.12)

Education: -0.154 (0.44)

Quality of life: 0.13 (0.51)

Homicide/suicide: -0.03 (0.86)

% GDP in tax/inequality: -0.65 (<0.01)

Happiness/income: 0.62 (<0.01)

Trust/income: 0.56 (<0.01)

Overseas Aid

2010-06-16T14:02:00.001+01:00

[This footnote relates to Chapter 6 of The Spirit Level Delusion]

Since The Spirit Level Delusion was published, I have come across the Index of Global Philanthropy and Remittances (2009) which provides overseas aid figures for 22 countries. Crucially, this index combines state aid with private donations. Shown as a percentage of gross national income, it is clear that more equal countries are neither more nor less generous to the developing world than the less equal countries. Wilkinson and Pickett are only able to argue otherwise by ignoring all private donations.

Case study: Life expectancy

2010-05-17T02:50:00.000+01:00

One of the central claims of The Spirit Level is that 'less equal' countries have lower life expectancies than more egalitarian countries. Its authors claim that the psychological stress of living in a less egalitarian society affects the health of all—rich and poor—and that this manifests itself in lower life expectancies.

To demonstrate this they show a graph that looks very much like this:

Inequality is shown on the horizontal axis and is the difference between the richest 20% and the poorest 20% (eg. in Sweden, the richest 20% are 4 times wealthier than the poorest 20%). As you can see from the graph, there seems to be a downward trend in life expectancy from the more equal countries, especially Sweden and Japan, to the less equal countries. The low life expectancies of Denmark and Finland should make us wonder whether this graph really proves that egalitarianism results in good health, but a broad correlation remains nonetheless.

But there are two major problems. Firstly, a number of wealthy societies are missing from this graph. In particular, where are Hong Kong, South Korea, the Czech Republic, Slovenia? All of them are wealthier than Portugal and should be shown.

Secondly, there are questions over the data used to ascertain life expectancy. Wilkinson and Pickett use figures from the United Nations Human Development Report, a respected and accurate source, but they use data from the 2004 edition. This is an odd choice because elsewhere in The Spirit Level, the authors rely on the 2006 edition. They even use life expectancy figures from the 2006 report elsewhere (the graph on page 7) so we know they were aware of them.

This is their reference for a graph they use to show life expectancy earlier in the book...

But this is their reference for their graph showing life expectancy against inequality...

So why the use of old statistics and a carefully selected sample group? If we look at the data from the UN's 2006 report—and include all relevant countries—a very different picture emerges.

The association between inequality and life expectancy has disappeared, replaced by a modest trend in the opposite direction. And to prove that the 2006 report is not an anomaly, here are the results from the 2009 report:

Again, there is no correlation. Indeed the three worst performing countries have a very equal distribution of wealth (Czech Republic, Slovenia and Denmark).

It's worth noting that the inequality/life expectancy hypothesis is not new. It first came to prominence in a 1992 British Medical Journal article, written by none other than Richard Wilkinson. That article inspired a flurry of research and, in The Spirit Level, the authors refer to a “vast literature” on the subject. There is, however, no mention of how much of this vast literature was written by Wilkinson himself, nor that much of the rest was critical of his theory.

His BMJ study was debunked at length in the same journal in 1995 by Ken Judge. Judge pointed out numerous errors in Wilkinson’s research, including the use of “inappropriate” data. He criticised Wilkinson for using the lowest 70% of families as a measure of inequality when a more conventional measure is the bottom 10% or 20% of individuals. “The suspicion,” wrote Judge, “must be that the choice is derived from the data” (ie. Wilkinson was cherry-picking).

When Judge recalculated the data based on the more usual measure of income per head, the association between life expectancy and inequality disappeared. Judge concluded:

In retrospect, it seems extraordinary that a predominantly monocausal explanation of international variations in life expectancy should ever have been regarded as plausible. It is much more likely that they are the product of many influences, which probably interact over long periods of time.

This was only common sense. Further studies conducted in Denmark and Japan failed to support Wilkinson’s hypothesis and although some studies showed an association between income inequality and life expectancy in the USA, other evidence showed that this was more likely to be due to education, underinvestment and other confounding factors. In 2002, a large study of wealthy European countries showed no association between inequality and life expectancy.

In The Spirit Level, Wilkinson and Pickett cite a 1996 editorial from the BMJ which discussed the “big idea” that “the more equally wealth is distributed the better the health of that society.” At that time, the BMJ was broadly supportive of the theory but research into it was still in its infancy. Wilkinson and Pickett do not mention the editorial that appeared in the same journal six years later, which concluded:

Now that good data on income inequality have become available for 16 western industrialised countries, the association between income inequality and life expectancy has disappeared.

By the time The Spirit Level was published, the slender circumstantial evidence upon which Wilkinson had made his case had been obliterated with the passing of time. Rather than change the theory to fit the facts, he and Pickett ignored the facts and persisted with the theory. In practice, that meant using old data when they were quite aware that more recent data was available.

God and the movies

2010-05-16T16:40:00.000+01:00

Maybe it's because I'm a bit of a statistics nerd, but once I start comparing countries, I find it difficult to stop. The fact is that associations are everywhere and the possibilities opened up by ecological epidemiology are endless. For example, here are two statistically significant associations showing belief in God and cinema attendance (against inequality).

Based on the World Values Survey. 'How important is God in your life?' Percentage answering 'very important'.

Based on Nationmaster data.

I show these graphs because they happen to show a strong correlations—stronger than most of The Spirit Level graphs. They are, as Wilkinson and Pickett might say, too strong to be the result of chance. But if they are not due to chance, how do we explain why people in less equal countries are more likely to believe in God and more likely to go the cinema? Does egalitarianism cause atheism? Does religion cause inequality? Or does going to the cinema make people believe in God?

The possibilities are limitless. But even if you exclude chance as a possibility (and that would be very hasty), explaining them in terms of income inequality requires a vivid imagination and a near-obsession with wealth redistribution.

As ever, our willingness to accept statistical associations depends on our susceptibility to the underlying message. Perhaps a socialist atheist would find these associations compelling. Or maybe a Christian film buff could use them as an argument in favour of capitalism. The rest of us might shrug our shoulders and say 'so what?'

US states

2010-05-16T15:58:00.000+01:00

[This is a discussion of the issues mentioned on page 15 of The Spirit Level Delusion]

The Spirit Level Delusion focuses on differences between nations. It does not look at differences between US states. There are several reasons for this.

Firstly, since—as I show—inequality does not influence outcomes on an international level, it is highly improbable that it would influence outcomes between regions within a country. Although the USA is a diverse place, there are greater cultural differences between, say, Israel and Japan than there are between Texas and California. Perhaps this explains why, even by the standards of The Spirit Level, the correlations shown for US states are weak. It is a stretch to say that the graphs they show on, for example, pages 59 and 141 are indicative of a genuine causal relationship.

Secondly, a discussion of US states would make the book twice as long and, for the reasons above, this would be an unnecessary strain on both reader and author.

Thirdly, and most importantly, the health and social problems highlighted in the USA are more plausibly associated with absolute income than with inequality. Wilkinson and Pickett deny this, but their own evidence contradicts them. On page 22 of The Spirit Level, they show two graphs. The first shows their index of health and social problems against inequality, the second shows the same index against 'national income' (this must be a mistake—they surely mean 'state income'). These data are shown below.

Wilkinson and Pickett state that the second of these graphs shows no association between income and health and social problems, but even the casual reader can see that this is not true. Clearly, the worst afflicted states are the poorest. Wilkinson and Pickett divert the reader's attention from this fact by not showing the linear regression line. Had they done so, the graph would have looked like this...

There is a reasonably strong correlation here. The poorest states do worse and none of the richer states do badly. It is, however, worth asking why the correlation is not even stronger. The answer lies in the dozen states in the bottom left corner. These states do not show a close fit, but that won't concern the people who live there. All these states are doing better than would be expected from their income. This is no great surprise. These are sparsely populated, predominantly rural, ethnically homogenous Northern states like North Dakota, Wyoming and Montana. No one pretends that wealth is the only factor that makes a state or country successful, but as this graph shows, it certainly helps. Look at the top right-hand corner. Those are the states that have higher state incomes but perform badly. Don't see any? Exactly.

Connecticut, Massachusetts and New York hold the key to understanding this data. They are outliers in Wilkinson and Pickett's inequality graph (above) and consistently fail to follow the pattern in The Spirit Level's other graphs. How three very unequal states do so well is an important question which Wilkinson and Pickett never address, but the answer is simple. They do well because of their wealth—inequality is irrelevant. Massachusetts performs so well because it is the third richest state. Connecticut and New York are outliers on the inequality graph but are a perfect fit on the income graph.

Mississippi and Louisiana perform very poorly under most criteria. They have the lowest life expectancies and the highest rate of infant mortality of any US states. But they are also the poorest and third poorest states respectively. This, more than inequality, must be considered the real driver of outcomes in these states.

We cannot rule out some indirect effect from inequality, but any effect is far from proven. The apparent correlation between inequality and outcomes is not, in itself, reason enough to cry causation. Other factors, such as the proportion of African-Americans in the population (shown below), show a stronger correlation but here, too, it would be foolish to insist on a direct causal relationship.

Many other such graphs could be created showing strong correlations—some valid, some spurious—and that is only to be expected. Outcomes in societies are dependent on countless cultural, political, economic and demographic factors that interweave over many years. This is an obvious point to make, but in the light of The Spirit Level's monocausal 'theory of everything', it is one that needs to be reasserted.

Graphs and sources

2010-05-16T02:14:00.000+01:00

All the statistics in The Spirit Level Delusion are there to be checked. Here are the sources...

Life expectancy

See Chapter 1 of The Spirit Level Delusion and case study.

Source: UN Human Development Report (2006)

Quality of life

See Chapter 3 of The Spirit Level Delusion

Source: The Economist Intelligence Unit’s quality-of-life index, 2005

Homicide (without USA)

See Chapter 4 of The Spirit Level Delusion

The 'link' between inequality and homicide rests on the USA's unusually high murder rate. When this obvious outlier is excluded, the association disappears. A correlation that depends on one outlier is, of course, no correlation at all.

All this data comes from the 1990s. Portugal's murder rate has since fallen to around the same level as Sweden, further undermining the inequality hypothesis.

Source: United Nations Surveys on Crime Trends and the Operations of Criminal Justice Systems (CTS) (1990-2000 average)

Involvement in the community

See Chapter 3 of The Spirit Level Delusion

Source: World Values Survey (go to 'Online data analysis')

Happiness

See Chapter 3 of The Spirit Level Delusion

Source: World Values Survey (go to 'Online data analysis')

Happiness against national income

See Chapter 3 of The Spirit Level Delusion

Contrary to Wilkinson and Pickett, there is ample evidence that economic growth benefits the population even at a very high level of development. The happiness survey is one example of this.

Source: World Values Survey (go to 'Online data analysis')

National income figures: World Bank 2008

Births to women aged 15-19 years

See Chapter 3 of The Spirit Level Delusion

There is no association with inequality for the majority of countries. Rates tend to be somewhat higher in English-speaking countries, but the rate in countries like Hungary, Hong Kong and Singapore suggest that this is not due to inequality. The slightly higher rate in Portugal is more likely to be due to the higher incidence of teen marriages and abortion being illegal when this data was collected.

Source: UNICEF and United Nations

Divorce

See Chapter 3 of The Spirit Level Delusion

Source: Americans for Divorce Reform

Prisoners per 100,000

See Chapter 4 of The Spirit Level Delusion

Source: United Nations Surveys on Crime Trends and the Operations of Criminal Justice Systems (CTS) (Ninth edition, or earlier when unavailable)

Recorded crime per 100,000

See Chapter 4 of The Spirit Level Delusion

There is an inverse relationship between inequality and the crime rate. There is also—but not always—an inverse relationship between the prison rate and the crime rate.

Source: United Nations Surveys on Crime Trends and the Operations of Criminal Justice Systems (CTS) (Ninth edition, or earlier when unavailable)

Education

See Chapter 9 of The Spirit Level Delusion

The countries of Southern Europe tend to perform least well but the performance of places like Hong Kong and Australia—as well as the lack of any statistically significant association—strongly suggest that inequality is not the cause of this.

Source: The Programme for International Student Assessment (PISA). Combined maths, literacy and science scores (2006)

Government spending on foreign aid

See Chapter 6 of The Spirit Level Delusion

Source: OECD (2008)

Per capita donations to charity

See Chapter 6 of The Spirit Level Delusion.

The trend towards more equal countries giving more in state aid is counter-balanced by the tendency for less equal countries to give more in individual, voluntary donations.

Source: Salaman (1999). See also Charities Aid Foundation (2006)

Sources for other graphs shown in The Spirit Level Delusion:

Inequality: UN Human Development Reports. Same methodology used as in The Spirit Level.

Smoking rates: Nationmaster

Unemployment: UN Human Development Reports.

Alcohol Consumption: World Health Organisation (2004)

Infant mortality: United Nations World Population Prospects (2008)

Obesity: International Obesity Taskforce

Recycling: Planet Ark (2004)

Foreword by Patrick Basham

2010-05-15T21:23:00.000+01:00

In recent years, anti-capitalist treatises have done very well on the bestseller charts and also atop many a book reviewer’s ‘Best of the Year’ list. The most obvious example of this tendency of book buyers and critics alike to embrace statist economic thinking is The Spirit Level: Why more equal societies almost always do better, written by Richard Wilkinson and Kate Pickett. Although Snowdon reserves some of his analytical slings and arrows for several of Wilkinson and Pickett’s ideological soul mates, most of his considerable empirical arsenal is unleashed on the arguments presented in The Spirit Level.

When Christopher Snowdon first talked about The Spirit Level with me, we discussed the book’s supposedly avant-garde thesis. Both of us were surprised that such an anachronistic perspective on economic policy could strike so many members of the media and the political class as both new and relevant to our current economic predicament. Crudely stated, Wilkinson and Pickett advocate that the State (or, rather, those Wise Persons who control the levers of State power) play a zero-sum game with our economic lives.

For me, personally, Wilkinson and Pickett’s thesis brings back vividly unpleasant memories of an undergraduate year in the mid-1980s that I spent, in part, being taught about socio-economic matters by my sociology tutor, a newly-minted Marxist feminist PhD. She had little tolerance for my ‘tax cutting equals economic growth equals more employment’ economic model, which she termed, ‘An ungodly synthesis of the worst of Reaganism and Thatcherism’ (which I thought oddly religious rhetoric for such a fanatical atheist). ‘On the contrary, Patrick,’ she would inform me, ‘you need to get over your fixation with economic growth. Rather than putting all our effort behind growing the economic pie, we should instead limit the pie to its current size, and then focus our energies on the issue of how we shall divide it up.’

There it was: Eighties-style socialist fundamentalism in a nutshell. Two sentences that encapsulated the British Labour Party’s economic thinking at the height of the Left’s control of the party and at the nadir of the party’s electoral relevance. Fortunately, I thought at the time, and for some time afterwards, such thinking has had its day. But I was wrong.

Analogous to an Economic Groundhog Day, our polity continues to relive the economic debate of the early 1980s, which hung on the question: Is a tightly regulated, high tax, nationalised economy better for society than a deregulated, low tax, privatised one? Many of us thought, naively it turns out, that question was answered a generation ago with a resounding, No. With the advantage of hindsight, however, it is clear that we were correct only in an empirical sense. In the political world, the economic flat-earthers never went away; they merely faded into the policy background to await their next moment in the fiscal sun, which arrived in 2008 in the form of a global recession. And, over the past two years, how the Wilkinsons and Picketts of this world have enjoyed their intellectually lazy, empirically hazy days of summer.

Hence, the need for an intellectual push-back the likes of which Christopher Snowdon so comprehensively provides in this volume. Most impressively, perhaps, Snowdon’s refutation of Wilkinson, Pickett et al. is both measured and finely balanced. When confronted with arguments and ‘facts’ that constitute little more than ‘junk economics’, it is very tempting, although rarely advantageous, to focus upon either the ignorance or the ineptitude of the researcher(s) in question. To his considerable credit, Snowdon resists the temptation to match his opponents’ tactics.

In striking contrast to so much contemporary anti-capitalist rhetoric, Snowdon’s words are calm, considered, and constructive. He simply lets his impressive empiricism do the talking for him. Having marshalled an immense body of evidence, he needs neither overheated language nor overblown conclusions.

Snowdon’s serious and careful treatment of his subject illustrates what, on our better days, we hope the Democracy Institute is all about. His ability to find the methodological flaws within specific pieces of research, unearth and explain contrasting pieces of research, and present this set of conclusions in an accessible manner is a skill possessed by a comparative few and one for which his readers should be thankful.

I am especially thankful for the realisation that, although I am an alleged expert in several of the specific areas covered in his book, I learned a considerable number of interesting things while reading it. I strongly suspect that everyone who reads this book will experience similar growth.

Patrick Basham

Democracy Institute

London

April 2010

Working hours

2010-05-15T18:50:00.000+01:00

On page 224 of The Spirit Level there is a graph showing working hours against inequality. This graph is taken verbatim from an obscure article titled 'Emulation, inequality, and work hours: Was Thortsen Veblen Right?' (published November 2003 and available to read here).

It looks like this:

There are several aspects about this graph that set it apart from others shown in The Spirit Level.

For one thing, it uses a very different measure of inequality. In The Spirit Level, Wilkinson and Pickett use the gap between the highest and lowest 20% of earners. The graph above uses the ratio of rich to middle (90th:50th percentile). This has a dramatic effect on where the countries appear on the inequality spectrum. For example, it makes France suddenly much more unequal than the UK and Italy.

Secondly, we can only identify 10 countries. We don't know whether the unidentified countries are rich or poor, nor do we know if all the countries studied in The Spirit Level are shown here. Where, for example, is Japan?

In short, the graph Wilkinson and Pickett use is not comparable to their other graphs. Rather than relying on a solitary article, the best practice would be to seek out the actual figures and plot a graph along the same lines as the others in The Spirit Level. If we do that, a very different picture emerges:

The data for this come from the OECD and relates to 2004. Only OECD countries are shown, hence no Israel, Slovenia, Singapore or Hong Kong. There is no significant correlation between long working hours and inequality. Korea and Greece work the longest hours despite being neither particularly equal nor particularly unequal.

Some of the Northern European countries (the Netherlands, Germany, Belgium, France) work fewer hours but one only needs to compare the least equal nations (Portugal, the USA) to the most equal nations (Japan, the Czech republic, Finland) to see that there is little difference and that, therefore, it is highly unlikely that working hours are dictated by inequality.

A much stronger association can be seen if one compares working hours against national income. There is a suggestion in the graph below of working hours declining as countries grow wealthier.

This correlation between wealth and shorter working hours is supported by historical data. The graph below comes from the article cited by Wilkinson and Pickett (above). The trend towards shorter working hours in the past 50 years (indeed, the past 100 or 200 years) is undeniable. The decline has levelled off in several countries since around 1990. It would be interesting to see figures from 2000-10.

The balance of evidence suggests that shorter working hours are associated with national income, not income equality.

Women's empowerment

2010-05-15T18:08:00.000+01:00

On page 60 of The Spirit Level, a graph appears showing 'women's status and inequality in rich countries'. According to Wilkinson and Pickett, this graph shows that "there is a tendency for women's status to be better in more equal countries" and that "the link between income inequality and women's status cannot be explained by chance alone."

The graph uses an index of Wilkinson and Pickett's own devising which is impossible to replicate or verify. There is, however, a ready-made index of gender empowerment used by the United Nations. The graph below shows data as displayed in Wilkinson and Pickett's favoured 2006 edition of the UN's Human Development Report.

Plainly there is no correlation with inequality. The Scandinavian countries do better while the two most equal Asian countries do particularly badly. (There is no data for Hong Kong).

Loneliness

2010-05-15T17:54:00.000+01:00

An important argument put forward in The Spirit Level is that people in less equal societies feel alienated and lonely. This, say Wilkinson and Pickett, goes hand-in-hand with the breakdown of community life. As I show in The Spirit Level Delusion, there is no evidence that people in countries such as the USA and Australia are less involved in the community than the people of Japan and Scandinavia. If anything, the reverse is the case.

One other small piece of evidence is worth mentioning. The data in the graph below come from an international survey of 15 year olds which asks them whether they agree with the statement 'I feel lonely'. This comes from the UNICEF report on child well-being (2007) and the results are shown below.

There are no data for the USA, Korea, Singapore, Slovenia or Hong Kong. I have excluded Japan from the graph to maintain scale but only because this very equal nation has a 'loneliness' score of 51%, a quite extraordinary figure when all the other countries come well under 10%.

As ever, I am reluctant to claim any kind of cause-and-effect here. Without an explanation for the correlation, it is foolish to cry causation. This graph does, however, act as further evidence that people in more equal countries are not happier, less alienated or less lonely.

Cancer survival

2010-05-15T12:36:00.000+01:00

Based on 5-year survival for breast, colorectal, and prostate cancer. From 'Cancer survival in five countries: a worldwide population-based survey (CONCORD)', M. Coleman et al., Lancet Oncology, 2008

Publication date & book launch

2010-05-05T13:24:00.000+01:00

The Spirit Level Delusion: Fact-checking the Left's New Theory of Everything will be published on 17th May 2010.

The book launch will be held at the Institute of Economic Affairs on 11th May at 6.30pm. To attend please RSVP here.

Alexis de Tocqueville

2010-05-01T18:55:00.000+01:00

I discuss Wilkinson and Pickett's misrepresentation of Alexis de Tocqueville in chapter 9 of The Spirit Level Delusion. To imply, as they do, that Tocqueville was an early socialist is laughable (you can read what he thought of socialism here).

There is one thing to add regarding Tocqueville's admiration of the 'equality of conditions' enjoyed in 1830s America. Anyone who has read Tocqueville's work (or, indeed, understands 1830s America) will be aware that he was referring to what we would today call equality of opportunity or equality of status. He certainly was not talking about equality as defined by Wilkinson and Pickett, ie. equality of outcome.

'Equality of conditions' is a somewhat ambiguous phrase which, as Hugh Brogan explains in his biography of Tocqueville, relies on a mistranslation:

Equality of status, or in AT's French, egalite des conditions. This is usually translated as 'equality of conditions', but this is misleading since nowadays it seems to imply economic equality, which AT knew perfectly well did not exist any longer in America, if it ever had...

In context it is perfectly clear what AT was concerned with, but not everyone has always remembered the context.

'Alexis de Tocqueville: Prophet of democracy in the age of revolution', Hugh Brogan; p. 275

[A new version of Tocqueville's Democracy in America is available here. The entire English translation can be downloaded for free here.]