• Health inequalities
• social mobility
• Nordic welfare state
• ability
• inequalities
• social factors
• social policy

In recent years, a number of major studies have suggested, paradoxically given their focus on equity, that the Nordic welfare states do not have the lowest (relative) socio-economic health inequity in Europe.1–3 We wish to argue that this could be an artefact of the method employed in such studies. In short, the composition of socio-economic groups within a country is itself a product of the welfare state type under investigation. This makes it very difficult to evaluate welfare states by studying socio-economic group difference in health within countries and then comparing this difference between countries, the method commonly used.

There are a number of ways in which the policies of different welfare states could influence the composition of apparently similar socio-economic groups. One example is the extent to which children, irrespective of background, are able to achieve their educational potential and then a job matching this ability. In a meritocratic society, the achievement of socio-economic position will reflect ability, irrespective of background, and there will, therefore, be a greater variation in ability, between social groups, than in a society with less social mobility. Importantly for studies of health equity, if ability were to have an impact on health that was independent of socio-economic position, then in a meritocratic society there would also be a concentration of ability-related health in higher socio-economic …