Richard Wilkinson and Kate Pickett The Spirit Level: Why More Equal Societies Almost Always Do Better (London: Penguin, 2009). xvii + 331 pp.

This brilliant book demonstrates beyond any reasonable doubt that economic equality is good for society. In doing so, it exposes the complete falsity of the dominant view that massive inequalities are a necessary condition for improving the quality of life in contemporary developed societies like Ireland.

The book has many virtues, the chief of which is to provide a mass of empirical evidence that societies with greater equality of income almost always do better than societies with more inequality, on a wide range of indicators. The overall argument is summarised in the following two graphs, which plot the level of income inequality against an index of health and social problems for the 21 large developed countries for which data are available and also for the 50 US states.

The index is composed of indicators of measures of life expectancy, educational performance, infant mortality, homicides, imprisonment, teenage births, trust, obesity, mental illness including addiction and social mobility. What Wilkinson and Pickett show is not just that, taken together, there is a strong connection between the overall index and inequality, but that each of the indicators taken separately is also strongly connected to inequality (chapters 4-12). If you do not have time to read the book, or even the rest of this review, you should at the very least look at the very accessible summary of this evidence at the Equality Trust’s website.

One might naturally suspect that the reason for these strong correlations is that the life expectancy, educational performance, imprisonment rates and so on experienced by poor people are particularly bad, and that the reason more unequal societies do worse is because of their higher poverty rates. Wilkinson and Pickett show, however, that the reason more unequal societies do worse is not just because they have more poor people, but because every section of society does worse than the corresponding section in more equal societies (chapter 13). For example, the infant mortality rate of the best off fifth of the British population is significantly worse than that of the best-off fifth of the Swedish population. (In fact, it is also worse than that of every fifth of the Swedish population - p. 184.) Literacy scores are lower for the children of college-educated Americans than for the children of college-educated Finns, Belgians and Britons (p. 109). In general, every stratum of society is worse off in more unequal societies than in more equal ones. That is why these societies are so much worse off overall, and also why every social class, except perhaps the very rich - the true capitalist class - would be better off in what really matters in life if their societies were more equal.

Being epidemiologists by profession, Wilkinson and Pickett are well able to rebut suggestions that these are statistical flukes, or that they are mere correlations rather than causal relationships, or that it is somehow ill-health and high infant mortality that cause greater inequality. They demonstrate convincingly that it is inequality that causes social ills (chapter 13). So if anyone you know would rather live in a society with greater trust, longer life spans, less crime, less violence, and so on, you can confidently maintain that they should be calling for a much more equal society.

One of the powerful features of Wilkinson and Pickett’s analysis is that it is based on comparisons of existing market economies. You do not have to tell your friends that we need to have a socialist revolution to bring about the kinds of improvement they purport to wish for, only that we need to establish the level of equality found in Sweden, Finland or Japan. So nobody can tell you that such changes are simply impossible. Wilkinson and Pickett also provide compelling evidence to show that greater equality is more deeply engrained in millennia of human experience than the levels of inequality found in Ireland, Britain and the US, so anyone who claims that it is contrary to human nature to live in more equal societies can be shown plenty of evidence that this is not the case (see chapter 14 in particular).

In light of such powerful evidence, why is it that the majority of political leaders in Ireland refrain from demanding much greater equality? Perhaps it is their ignorance of the facts Wilkinson and Pickett so compellingly marshal. Perhaps they continue to believe, contrary to the evidence, that social ills are a function of overall national income rather than its pattern of distribution. Many of them seem to think that policies for greater equality would scare off investors, without enquiring how it is that capitalists continue to invest in societies that are much more equal than ours. Or perhaps they think - and may be correct in thinking - that until a much larger proportion of Irish citizens demand more equality, there is no electoral advantage in proposing it. One thing for sure is that Wilkinson and Pickett’s evidence needs to be much more widely disseminated within Ireland if the movement for greater equality is to be strengthened.

Although The Spirit Level is a powerful, brilliant book, it has some limitations. Much of the book is concerned with explaining how inequality causes poor health and other social ills, and some of the explanations are more speculative than others. The dominant, overall explanation is that income inequalities are closely related to status inequalities, and that in modern societies inequality of status exacerbates social ills by increasing levels of stress and distrust throughout the social hierarchy. That is on the whole a persuasive explanation, but in individual chapters the explanation is not always so clear and convincing. For example, in chapter 8 the authors examine the link between inequality and educational performance. They provide very strong reasons for why educational attainment is worse among the worst-off groups in unequal societies than in more equal ones. But they do not seem to provide a clear explanation of why it is worse across the whole social hierarchy than in more equal societies.

A related limitation is the book’s relationship to the multidimensional and socially plural nature of inequality. Wilkinson and Pickett’s central argument relies on the connection between inequality of income and inequality of status, with inequalities of power, working conditions and personal relationships also playing their parts in different sections of the analysis. The groups they primarily compare are income groups (specifically different fifths of the distribution), although they occasionally look at gender and ethnicity. At the level of generality of their analysis, the fact that income inequalities do not always track those of status, power and care is not a major issue. Nor does their relative neglect of issues related to gender, ethnicity, disability, age and sexual orientation weaken the overall case they make for greater income equality. (They do show that there is a general, significant relationship between income inequality and gender inequality but their measure of gender inequality is limited, and they admit that there are major exceptions to the trend e.g. Japan and Italy.) But these issues do matter when one shifts from the specific issue of the benefits of income equality to the broader challenge of building a movement for egalitarian change. Such a movement needs to include a role for social groups whose claims for equality are not necessarily directly or closely linked to - and certainly not exhausted by - the objective of greater equality of income: women, ethnic minorities, disabled people, LGBT people, older people and children. Their equality claims may well involve issues of economic redistribution, but they also involve recognition, power, inequalities of working and learning and issues of love and care (see Baker et al., Equality: From Theory to Action). Wilkinson and Pickett rightly argue that nearly everyone would benefit from greater equality of income. But when we link that egalitarian demand to those others, it becomes even clearer that what they call the ‘river of human progress’ towards greater equality is a positive-sum game that holds out a brighter future for all of us.

John Baker is a senior lecturer at the Equality Studies Centre, UCD School of Social Justice