A Note on the decomposition of health inequality by population subgroups in the case of ordinal variables

G. Lv et al. proposed an axiomatic derivation of measures of health inequality in the case of ordinal variables. Not only is there great inequality across the peoples of the world in material standards of living, but there are also dramatic inequalities in health. This chapter shows that one of the health inequality indices axiomatically derived by Lv et al. is related to the Gini index and hence may be decomposed by population subgroups into the sum of three elements: between and within groups inequalities and a residual reflecting the extent of overlap between the distribution of health status in the various population subgroups. It argues that the distributions of the individuals of the two population subgroups, between the four health categories, do not overlap. There is certainly a strong need to better grasp the determinants and impact of health inequality.