Monitoring income-related health differences between regions in Great Britain: A new measure for ordinal health data.

The paper proposes a new measure of the extent to which differences in population health status between the regions of a country are systematically related to regional prosperity. The headcount index of income-related health stratification has a straightforward interpretation as the population-weighted mean difference in the probabilities that the healthier of any two randomly chosen individuals will be from the richer rather than the poorer region from which they are drawn. Moreover, it is well-defined even if only ordinal health data are available, being directly applicable to polytomous categorical variables without the need for either dichotomisation or cardinalisation. The new index is used to examine the evolution of income-related health differences between the regions of Great Britain over the period from 1991 to 2008.