Background A number of different socio-economic classifications have been used in relation to health in the United Kingdom. The aim of this study was to compare the predictive power of different socio-economic classifications in relation to a range of health measures.

Methods A postal questionnaire was sent to a random sample of adults in the West of Scotland (sampling from 1997 electoral roll, response rate 50 per cent achieved sample 2,867)

Results Associations between social position and health vary by socio-economic classification, health measure and gender. Limiting long-standing illness is more socially patterned than recent illness; income, Registrar General Social Class, housing tenure and car access are more predictive of health than the new National Statistics Socio Economic Classification; and men show steeper socio-economic gradients than women.

Conclusion Although there is a consistent picture of poorer health among more disadvantaged groups, however measured, in seeking to explain and reduce social inequalities in health we need to take a more differentiated approach that does not assume equivalence among social classifications and health measures.