Measurement of Inequity in Health Care with Heterogeneous Response of Use to Need

We propose a method of measuring and decomposing inequity in health care utilisation that allows for heterogeneity in the use-need relationship. This makes explicit inequity that derives from unequal treatment response to variation in need, as well as that due to differential effects of non-need determinants. Under plausible conditions concerning heterogeneity in the use-need relationship and the distribution of need, existing methods that impose homogeneity will underestimate pro-rich inequity. This prediction is confirmed for four low-middle income Asian countries.