Re-evaluating self-evaluation. A commentary on Jen, Jones, and Johnston (68:4, 2009)

Abstract

In a paper recently published in Social Science & Medicine, ‘‘Global variations in health: Evaluating Wilkinson’s income inequality hypothesis using the World Values Survey’’, and one in another journal Jen, Jones and Johnston provided analyses of selfrated health, using data from theWorld Values Survey (Jen, Jones, & Johnston, 2009a, 2009b). They showed that income is significantly associated with self-rated health; higher incomes being related to better health. Although they found that self-rated health varied between countries, they did not find an independent effect of income inequality on self-rated health. The authors concluded that their analyses provided a test, and refutation, of what they described as the ‘‘Wilkinson hypothesis’’. Briefly stated, the ‘‘Wilkinson hypothesis’’ is that population health in rich countries tends to be better in societies where income is more equally distributed. There are now more than 200 analyses of the nature of this relationship, and reviews of these studies have come to conflicting interpretations of the evidence, with researchers disagreeing over methodological issues, such as the scale at which inequality is measured, whether or not various control variables should be interpreted as confounders or mediators, and the appropriateness of various statistical models (Lynch et al., 2004, Macinko, Shi, Starfield, & Wulu, 2003, Subramanian & Kawachi, 2004,Wilkinson & Pickett, 2006). In the context of this controversy, do Jen et al’s (2009a, 2009b) analyses put a final nail in the coffin of the ‘‘Wilkinson hypothesis’’? In this paper, we consider the relationship between ‘health’ (the outcome in the Wilkinson hypothesises to be affected by income inequality) and ‘self-rated health’ (the outcome analysed by Jen and colleagues). We argue that ‘health’ and ‘self-rated health’ cannot always be assumed to be proxies for one another. We also suggest that if, as Jen et al. find, average levels of self-rated health tend to be higher in more unequal societies, that this has something to tell us about the psychosocial effects of living in unequal societies.