Welcome

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 an attempt to replicate The Spirit Level's findings after ten years, 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 Chapter 10 as a PDF.

"A devastating critique"
—The Economist

"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 myth of inequality as the root cause of just about all social ills is dismantled... Snowdon’s thorough appraisal of available data and literature, and examination of alternative causes – all underpinned by acerbic wit – sees to that." 
— Sam Hamilton, Medical Writing

"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 

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

The Spirit Level ten years on

Kate Pickett and some science

The Spirit Level turned ten this month. A minor publishing sensation when it was published in March 2009, it used a series of scatter plots to make the case that income inequality is a major driver of a range of health and social problems. The authors, Richard Wilkinson and Kate Pickett, argue that these problems are directly linked to the rate of inequality and will rise or fall as inequality rises and falls.

I argued in The Spirit Level Delusion (2010) that most of Wilkinson and Pickett's statistical correlations were the result of selection bias in the countries, criteria and datasets used by the authors. They looked at the 50 richest countries in the world (on the basis that these societies were wealthy enough to not benefit from further growth whereas outcomes in poorer countries would be confounded by the effect of GDP). However, they only used 23 of these countries - often fewer - in their analysis. The poorest of them was Portugal but several countries with a higher GDP than Portugal were excluded for no good reason. When I added these countries, many of the associations with inequality disappeared (see footnote 1).

I won't go into the other flaws in the book here, suffice it to say that if The Spirit Level hypothesis is correct, it should apply across space and time. Most of the data used by Wilkinson and Pickett (henceforth W & P) was published between 2000 and 2004. If their correlations are proof of a golden rule about inequality - 'a theory of everything', as the BBC put it - similar associations with inequality should emerge if we use data from 2010 to 2014 or any other period. In principle, it should be possible for the authors to publish a new edition of their book every few years showing consistent trends.

They did publish a sequel to The Spirit Level last year (I reviewed it here), but there was no attempt to create their graphs with new data. And so, on the tenth anniversary of the book's publication, I thought it would be interesting to put some of their most striking claims to the test, applying W & P's own methodology to up-to-date statistics.

I gathered recent income inequality statistics from the UN's Human Development Report (2018 edition). This is the same source used by W & P in The Spirit Level. For reasons that are never made clear, W & P preferred to use the 80/20 measure rather than the more usual Gini coefficient when comparing countries. Both measures give broadly the same results, but the Human Development Report no longer uses the 80/20 measure so I have used the Gini instead.

As you might expect, there have been changes in the rates of inequality in the last 10-15 years. The Scandinavian countries continue to have some of the lowest rates although inequality has risen in all of them except Finland. Inequality in Japan is significantly higher than was reported in The Spirit Level. Rates have also increased in Israel, Ireland, Spain and the USA, but fallen in the UK, Singapore and Belgium (see footnote 2).

Life expectancy

The Human Development Report (HDR) was also the source of life expectancy figures used by W & P. These formed the basis of perhaps their most famous claim, which Richard Wilkinson had been making since 1992, that life expectancy is directly linked to income inequality and that, therefore, inequality is bad for health.

As I noted in The Spirit Level Delusion, W & P opted to use the 2004 edition of the HDR for their life expectancy figures despite using the 2006 edition elsewhere. I believe this is because they would have been unable to find a statistically significant association with inequality had they used the figures from the more recent edition (p-value = 0.116996). Using the 2004 data, they were able to achieve statistical significance in the graph shown below (p-value = 0.031, r2 = 0.20), although the association disappears when countries such as South Korea are added to the analysis.

In The Spirit Level Delusion, I showed that no such correlation existed if one used later editions of the HDR. Using the most up-to-date figures for inequality and life expectancy, we can see that there is still no correlation, even if we confine the analysis to the 23 countries selected by W & P (R=0.02, r2=0.0004, p-value=0.93).

If we add the four countries that are unequivocally richer than Portugal and were excluded from The Spirit Level for no good reason (South Korea, Hong Kong, Slovenia and the Czech Republic (now known as Czechia)), there is a statistically significant association with inequality but it is in the opposite direction to that predicted by The Spirit Level hypothesis, with greater inequality correlating with longer life expectancy (r2=0.145, R=0.385, p-value=0.0495).

Obesity

After discussing life expectancy, W & P dedicate a chapter to the purported link between inequality and obesity. Again, they produce a graph showing a statistical correlation (see below). The correlation is highly dependent on the low rate in Japan and the high rate in the USA. It strangely excludes Singapore, which has a low rate of obesity and a high rate of inequality. If Singapore and the other two rich Asian countries are included, the positive association disappears (see The Spirit Level Delusion).

There are also question marks over some of the obesity estimates used by W & P. Internationally comparable obesity statistics were hard to come by when W & P wrote their book and they had to resort to a range of largely self-reported figures, some of which dated back to the mid-90s. Methods have since improved and it is possible to get a more accurate picture. In the graph below, I use figures from the World Health Organisation, except for Hong Kong and South Korea for which figures from Hong Kong's Centre for Health Protection and the OECD are taken respectively. 

Limiting ourselves to W & P's 23 countries, there is no statistically significant relationship (r2=0.0461, R=0.2147, p-value=0.33).

With all the countries included, the correlation is weaker still (r2=0.008, R=0.09, p-value=0.65).

Mental health disorders

Internationally comparable figures for mental illness prevalence were also patchy when W & P wrote their book. The graph they use to show that inequality drives mental health disorders (see below) suffers from multiple flaws. It only shows twelve countries, it excludes Singapore (again) despite W & P having included it in an earlier version of the graph (published in Oliver James' book Affluenza) and it cherry-picks figures from several different surveys which produce notably different results and are not comparable (see pp. 38-40 of The Spirit Level Delusion).

In the graphs below, I use figures from Our World In Data based on statistics from the Global Health Data Exchange (no figures are available for Hong Kong). Gathering reliable data on the prevalence of mental health disorders continues to pose problems (which the authors discuss here) but this dataset is much better than the pick-and-mix selection presented in The Spirit Level (and reproduced in The Inner Level - such is the importance of this purported finding to their hypothesis).

Using the latest inequality figures and the best prevalence data on mental disorders, there is absolutely no association between the two variables. This is true regardless of whether we use W & P's 23 countries (r2=0.069, R=-0.26, p-value=0.75)...

... or use the slightly expanded cohort (r2=0, R=0, p-value=1).

Homicide

A further claim in The Spirit Level is that inequality drives violence - murder, in particular.

As with W & P's claim about obesity, the statistical evidence for this claim relies heavily on the USA being an outlier. There is no correlation among the other 22 countries and, as I showed in The Spirit Level Delusion, there is no correlation when the full complement of rich countries is included.

Using recent homicide statistics from the UN Office on Drugs and Crime, we can see that there is no statistically significant association between inequality and homicide, even if we confine our analysis to W & P's 23 countries (r2=0.14, R= 0.37, p-value= 0.08). The inclusion of the other countries makes the correlation even weaker (r2=0.06, R=0.25, p-value=0.21).

Incidentally, although the USA continues to be a huge outlier among rich societies for homicide, its murder rate is lower than it was when W & P wrote The Spirit Level, contrary to their implicit prediction. Faced with growing inequality and a falling murder rate, W & P clutched at the straw of a slight upturn in the homicide rate in 2005-06. The murder rate had risen from 5.5 per 100,000 to 5.7 per 100,000 and W & P cited this as evidence that the effect of inequality was finally manifesting itself. I was a false dawn, however, and by 2014 it had dropped to 4.7 per 100,000. Although it has since jumped to 5.3 per 100,000, it remains lower than it was when W & P claimed that there is a 'reasonable match' between the rate of homicide and the rate of inequality. As the graph below shows - with homicides in red - there isn't (see footnote 3).

Teen births

W & P made the same rash mistake when discussing teen births in the USA. Their hypothesis suggests that teen pregnancies and teen births should be getting more common as income inequality grows. Alas for them, teen births had fallen to an all-time low when they started writing their book, but they took solace from another small upwards blip and announced that, in addition to the murder rate rising, 'in 2006, the teenage birth rate also started to rise again'. The birth rate for teenagers aged 15-19 rose from 40.5 per 1,000 females to 41.9 births per 1,000. It was the first rise in fifteen years but it was not the herald of an inequality-induced epidemic of teen pregnancies. By 2017, the rate had fallen to just 18.8 per 1,000.

The Spirit Level found a correlation between income inequality and teen births. Using recent teen birth figures from the World Bank and looking at W & P's 23 countries, there is still a statistically significant relationship (r2=0.247, R=0.497, p-value=0.016). 

However, this seems to be due to the selection of countries. When the four wealthy countries that were excluded from The Spirit Level are added, the correlation disappears (r2=0.06, R=0.24, p-value=0.219).

Infant mortality

Finally, I looked at another correlation in The Spirit Level that seemed reasonably robust at first glance.

As I showed in Chapter 5 of The Spirit Level Delusion, this is another example of a correlation that disappears when the full complement of countries is analysed. In that chapter, I was less interested in the statistical claim than the causal mechanism. There seems to be no practical way in which the 'psychosocial' impact of modest differences in income inequality could cause the birth defects and congenital abnormalities that are at the root of most infant deaths in rich countries.

Looking at the evidence anew, I use infant mortality figures from the most recent HDR (except for Hong Kong where the figure comes from Hong Kong's Department of Health because no figure is given in the HDR). There is no statistically significant relationship with inequality regardless of whether we study W & P's selection of countries (r2=0.15, R=0.39, p-value=0.07) or the expanded cohort (r2=0.045, R= 0.21, p-value=0.29).

In summary, most of the biggest claims made by Wilkinson and Pickett in The Spirit Level look even weaker today than they did when the book was published. Only one of the six associations stand up under W & P's own methodology and none of them stand up when the full range of countries is analysed. In the case of life expectancy - the very flagship of The Spirit Level - the statistical association is the opposite of what the hypothesis predicts.

If The Spirit Level hypothesis were correct, it would produce robust and consistent results over time as the underlying data changes. Instead, it seems to be extremely fragile, only working when a very specific set of statistics are applied to a carefully selected list of countries.




Footnote 1
W & P's justification for leaving so many countries out of the analysis is twofold. Some countries don't have inequality data and some countries are tax havens (and therefore have distorted inequality data). The first justification is bullet-proof and the second is at least arguable, but in their efforts to avoid tax havens, they simply assume that all countries with a population of under three million is a tax haven. This makes no sense. Not only does it allow two countries that are arguably tax havens to be included (Ireland and Switzerland), but it excludes countries like Slovenia that are clearly not tax havens. Slovenia is one of the most equal countries in the world and therefore should be a star performer. It should at least be in the analysis. There is no justification at all for excluding Czechia, Hong Kong and the Republic of Korea.


Footnote 2
Inequality figures for New Zealand, Hong Kong and Singapore are not included in the UN report. Gini coefficients for these countries come from the New Zealand government, Singapore's Ministry of Finance and Oxfam respectively. These estimates are similar to estimates from other sources. All Gini coefficients are post-tax and benefits.

The change in Japan's rate of inequality since 2006 is the most striking difference between the two sets of figures. However, it has always been debatable whether its rate of inequality was as low as it was shown in The Spirit Level. Some datasets showed Japan to have quite an average rate of inequality even in 2006.


Foot note 3
The period between 1910 and 1960 is a nice example of correlation not equalling causation. The two variables seem to be moving in broadly the same direction, initially rising and then falling sharply, with homicides slightly lagging behind inequality. In fact, inequality and homicide rise and fall for very different reasons. The murder rate rose during Prohibition, peaking in the early 1930s just before alcohol was re-legalised. Inequality rose until 1929 when the Wall Street Crash put it into reverse. The fact that these two events happened at around the same time is simply a coincidence (although the economic depression gave the government a reason to legalise - and thus tax - alcohol again). From the 1960s, the two trends go in completely different directions.



All R-values are Pearson Correlation Coefficients. All thresholds for statistical significance tests are p < .05.


Read the extra tenth chapter of The Spirit Level Delusion for free here.

Review: The Inner Level by Richard Wilkinson and Kate Pickett

Wilkinson and Pickett have written a sequel to The Spirit Level, titled The Inner Level. You can read my review of it here.

Homicide and teen births

Part of The Spirit Level hypothesis is that teen births and homicide are somehow caused by inequality (chapters 9 and 10). However, Wilkinson and Pickett face a problem insofar as inequality has been rising in most countries for many years while rates of teenage births and murder have been falling. They attempt to square this circle on page 142 when talking about their worst performer, the USA.

Homicide rates in America, after rising for decades, peaked in the early 1990s, then fell to their lowest level in the early 2000s. In 2005, they started to rise again. Similarly, after peaking in the early 1990s, teenage pregnancy and birth rates began to fall in America, and the decline was particularly steep for African-Americans. But in 2006, the teenage birth rate also started to rise again, and the biggest reversal was for African-American women.

The standard Gini measurement of inequality (see below) isn't very helpful to Wilkinson and Pickett in this instance since it shows inequality to have been rising pretty much continuously since the early 1990s which is exactly when the homicide and teen birth rates started to fall.

Faced with this obstacle, they resort to an obscure discussion paper which paints a quite different picture of the US trend, with...

...inequality rising through the 1980s to a peak in the early 1990s. The following decade saw an overall decline in inequality, with an upturn since 2000.

This finding is contrary to all other evidence and has been described as "the equivalent of the sun orbiting the earth", but it nevertheless allows Wilkinson and Pickett to triumphantly conclude...

So there is a reasonable match between recent trends in homicides, teenage births and inequality—rising through the early 1990s and declining for a decade or so, with a very recent upturn.

In other words, the 1990s saw falling inequality and therefore falling rates of teen births and homicide, whereas the Noughties saw rising inequality and therefore rising rates of teen births and homicide.

This is patently at odds with the facts. As I mentioned in The Spirit Level Delusion, it is a stretch to say that the homicide rate "started to rise again" in 2005. In fact, there was a tiny blip in 2005-06 when the murder rate went from 5.5 per 100,000 to 5.7 (see below). After that, the downward trend returned. By 2011, it was 4.7 per 100,000.

Moreover—and the reason for this little blog post—I recently had cause to look up the US's teen birth rates which last year "reached historic lows for all age and ethnic groups". Here too we see a little blip in the middle of the Noughties followed by a continued decline.

The Spirit Level was published in 2009 and so the data from the most recent years were naturally not included. Nevertheless, it was, at best, rash of its authors to present a slight upturn in the figures as the start of an inequality-fuelled rising trend. No matter which set of inequality figures one uses—and the Gini figures are vastly more credible—Wilkinson and Pickett's argument does not stand up.

We now know for certain that the small increase in the homicide and teen birth figures in 2005-06 was just a blip. The facts are quite clear. Inequality has been rising in the USA while the homicide and teen birth rates have been falling. There is simply no correlation between these variables. We need to look elsewhere for an explanation.

The Spirit Level Delusion: Chapter 10

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).

Thanks,

CJS

Prof. Colin Mills on The Spirit Level

Colin Mills, professor of sociology at Oxford University, makes some very worthwhile observations about The Spirit Level on his blog. Perhaps mischievously, Mills describes himself as "merely a sociologist" (Richard Wilkinson's qualifications are in history and sociology) and he confines himself to the chapter about inequality and health—Wilkinson's speciality. He notes that Wilkinson and Pickett misrepresent the evidence base, ignore studies which do not support their hypothesis and fail to adequately reply to their critics.

On a personal level, I was interested to see that he spotted that Figure 2.5 of The Spirit Level indicates that there is a relationship between health and income in the US. This was one of the graphs that first got me interested in testing The Spirit Level hypothesis back in 2009. Wilkinson and Pickett do not comment on the obvious fact that all the states which score poorly on their 'index of health and social problems' have a lower-than-average per capita income. This is absolutely crucial in understanding why they find relationships, albeit often slight, with inequality elsewhere—the least equal states are also the poorest.

But wait a minute. My first reaction when I looked at Figure 2.5 was that actually there is quite a clear relationship between aggregate income levels and health/social problem outcomes in US states. Richer states have better outcomes even without special pleading for the influential peculiarities of Idaho, Wyoming, Montana....

At this point I began to lose a little confidence as you appear not to be playing it straight with your readers, not all of whom, I assume, will look too closely at the figures or be alert to what could be considered a bit of textual leger de main.

Indeed. I have briefly discussed this issue here.

Mills has done what 99 per cent of The Spirit Level's readers have not done (and should not have to do) and looked at the scientific literature which Wilkinson and Pickett so often misrepresent.

But I do want to read the systematic reviews myself and not just rely on being told what they say. Just as well really, for if I had to rely solely on the 456 citations in The Spirit Level I would never have come across the two lengthy articles written by Lynch et al. in (2004) for the Milbank Quarterly entitled 'Is income inequality a determinant of population health?'. Luckily I have well informed colleagues who could point me in the right direction. Of course you know what Lynch et al. conclude from their careful scrutiny of "98 aggregate and multi-level studies examining the association between income inequality and health". For the benefit of those readers who can't penetrate the pay-wall let me quote from their conclusions (pp 81):

"Among affluent countries does income inequality help explain international differences in population health? The evidence suggests that income inequality is not associated with population health differences - at least not as a general phenomenon - among wealthy nations. Do levels of income inequality explain regional health differences within countries? In aggregate-level US studies, the extent of income inequality across states and metropolitan areas seems reasonably robustly associated with a variety of health outcomes, especially when measured at the state level. In multilevel US studies, using both individual and aggregate data, the evidence is more mixed, with state-level associations again being the most consistent. For other countries, the aggregate and multi-level evidence generally suggests little or nor effect of income inequality on health indicators in rich countries...but there may be some effects in the United Kingdom." [my emphasis].

Strange that you don't mention Lynch et al.'s papers (I know you cite them in your own review article but without, as far as I can see, any serious effort to explain why they get such different results to your own). Odd in several respects: firstly it was probably the most comprehensive independent (ie not counting papers written by yourselves) systematic review of the evidence on health then published when you were drafting The Spirit Level. Secondly, because it is not completely unfavourable to your position. After all it concludes that there is some evidence of an income inequality effect in US state level data (and possibly in the UK) - though their second paper which examines time-series data casts more doubt on the US case. I simply cannot understand why you fail to mention it, or if it is flawed in some way, rebut it, refer to your own rebuttal published elsewhere (if there is one) or the rebuttals of others (if there are any). Over and over again you tell us that the weight of the evidence is on your side and that there is a broad consensus amongst experts working in the field. But this simply isn't true, is it? At the very least your now perplexed readers could be forgiven if they find your omission, well, a little shifty.

He also comments on Wilkinson and Pickett's misleading response to their critics, including John Goldthorpe (also a professor of sociology at Oxford University who, like Mills, identifies himself as politically left-wing).

My colleague wrote a somewhat critical review of the book which was published in a well known peer reviewed journal. After reading your "reply" I was again deeply puzzled. What you say has, at most, only tangential relevance to the substance of my colleague's criticisms. The casual reader of what you write would come away with the impression that some sociologist had made a rather footling objection to the effect that you hadn't paid enough attention "to the vast amount of careful work now available on social class classifications" [your words] - surely a case of the cobbler only having eyes for leather. But wait a minute, that is not at all the substance of the critique.

He also makes the point, which Peter Saunders makes in his critique Beware False Prophets, that Wilkinson and Pickett conflate 'more equal' societies with classless societies, and yet their most equal country—Japan—is anything but classless.

In Japan income inequality is less marked than in many developed nations and health outcomes are comparatively good. This would seem to conform to the Wilkinson-Pickett party line. But it is also the case that Japan is a highly status conscious (in the sociological sense) society. It is obligatory to acknowledge inferiority and superiority both in terms of behaviour and in terms of the use of honorifics. In any unfamiliar social situation the initial process of figuring out who is relatively inferior to whom is a source of considerable anxiety.

To put it simply, in Japan systematic inequality is strongly structured by considerations of social status, superiority and inferiority yet health outcomes are relatively favourable. If the relevant psycho-social mechanism is to do with social status (in any sociologically meaningful use of that term) then measuring status inequality by means of income-inequality puts Japan at the wrong end of the spectrum! This is much more than a petty point about occupational coding, but you wouldn't guess that if all you had to go on was The Spirit Level.

Mills' whole post is worth reading in full here.

Well, by now if you haven't already lost patience and dismissed me as yet another enemy of equality, you are probably muttering that you have dealt with all this before if only I would care to read more of your own work. The thing is, I have read it, and I'm not the only one to notice in it a recurrent pattern. Time after time you tell critics that you have dealt with their objection in one or another of your publications but when I turn to them what I find is indeed a reference to your critics, but not an actual response to the exact criticism they make and often a discussion of some quite unrelated issue. Why you do this is, to me, quite baffling...

So, in the end Professors Wilkinson and Pickett, you face a credibility gap. People like myself who want, broadly speaking, the same things as yourselves can find the time to ferret out, read and consider the evidence you don't tell us about. Joe Public, which I take it The Spirit Level is aimed at, has neither the time nor the access to the primary sources, let alone the training to make an informed judgement. They have to take what you say on trust. That is why university professors speaking with all the lustrous institutional prestige that implies have, in my opinion, a duty to be scrupulously honest, especially when writing for a popular audience. And when the brickbats come they should not be able to get away with emphasizing the popular nature of their writing whilst ducking behind the protective shield of peer review. What we all need are better reasons to believe. I'm not the only social scientist or social democrat who thinks you haven't yet given us nearly enough.

Inequality and anxiety

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 inequality...

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

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 in equality 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 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 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...