Friday, 23 July 2010

The Spirit Level, the Policy Exchange and the race card

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]

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