Tuesday, 13 November 2012

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).



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.