Measuring equity in access to health care.

This article develops and uses methodologies to: (1) measure equity in the distribution of access to health services; and (2) measure the impact of health insurance programs on equity. The article proposes two egalitarian-based indicators for measuring equity in terms of access to health care--a concentration coefficient derived from the Gini coefficient, and the Atkinson distributional measure and also employs a weighted Utilitarian social welfare function to measure overall levels of access. The article defines access as the use of health care by individuals with a need for care; need is measured as self-reported morbidity. The setting for the empirical application is the country of Ecuador. The Ecuador Social Security Institute runs a General Health Insurance (GHI) program, whose affiliates are primarily workers in the formal sector of the economy. The principal data source is the 1995 Ecuador Living Standards Measurement Survey. The study uses a microeconomic health care demand model and bivariate probit estimation techniques to measure the impact of insurance on health service use for each quintile of adjusted per-capita household expenditure. The study also predicts health care use and program impact for each quintile under a series of simulation scenarios corresponding to proposed expansion of eligibility for the GHI program. The GHI program increases overall access to health care, but has a negative impact on equity in the distribution of health services. The benefits of the program, calculated as its marginal impact on the probability of using of health care, have a strongly regressive distribution. Expanding eligibility to the self-employed makes the benefit more equitably distributed (but still inequitable), and increases overall social welfare considerably. Expanding eligibility to the dependents of the insured person has similar effects, although less important in magnitude.