The inequality of medical expenditures for several years in a healthy, nonelderly population.

Previous studies have shown that the distribution of annual medical expenditures for a population is very unequal and remains so for periods of more than 1 year. The authors use a better measure of inequality, the Gini coefficient, to test its persistence for longer periods. This measure is applied to data collected from the Rand Health Insurance Experiment. The experiment enrolled a nonelderly population typical of those covered by employer health plans for periods up to 5 years. The distributions of annual expenditures for this population are highly unequal, in line with previous studies. Inequality declines substantially when longer periods are considered.