Measuring Ex-Ante Welfare in Insurance Markets

Abstract

The willingness to pay for insurance captures the value of insurance against only the risk that remains when choices are observed. This paper develops tools to measure the ex-ante expected utility impact of insurance subsidies and mandates when choices are observed after some insurable information is revealed. The approach retains the transparency of using reduced-form willingness to pay and cost curves, but it adds one additional sufficient statistic: the difference in marginal utilities between insured and uninsured. I provide an approach to estimate this statistic that uses only reduced-form willingness to pay and cost curves, combined with either a measure of risk aversion. I compare the approach to structural approaches that require fully specifying the choice environment and information sets of individuals. I apply the approach using existing willingness to pay and cost curve estimates from the low-income health insurance exchange in Massachusetts. Ex-ante optimal insurance prices are roughly 30% lower than prices that maximize market surplus. While mandates would increase deadweight loss, the results suggest they would actually increase ex-ante expected utility.