Information Frictions and Adverse Selection: Policy Interventions in Health Insurance Markets

This paper develops and implements a general framework to study insurance market equilibrium and evaluate policy interventions in the presence of choice frictions. Friction-reducing policies can increase welfare by facilitating better matches between consumers and plans, but can decrease welfare by increasing the correlation between willingness-to-pay and costs, exacerbating adverse selection. We identify relationships between the underlying distributions of consumer (i) costs (ii) surplus from risk protection and (iii) choice frictions that determine whether friction-reducing policies will be on net welfare increasing or reducing. We extend the analysis to study how policies to improve consumer choices interact with the supply-side policy of risk-adjustment transfers and show that the effectiveness of the latter policy can have important implications for the effectiveness of the former.