Externalities and Benefit Design in Health Insurance
研究了Medicare处方药保险市场中，私人保险公司的战略激励如何对传统Medicare项目产生财政外部性，并导致不同计划间药品覆盖差异，发现战略激励与不对称信息对福利设计同等重要。
Abstract Insurance benefit design has important implications for consumer welfare. In this article, we model insurer behaviour in the Medicare prescription drug coverage market and show that strategic private insurer incentives impose a fiscal externality on the traditional Medicare program. We document that plans covering medical expenses have more generous drug coverage than plans that are only responsible for prescription drug spending, which translates into higher drug utilization by enrolees. The effect is driven by drugs that reduce medical expenditure and treat chronic conditions. Our equilibrium model of benefit design endogenizes plan characteristics and accounts for asymmetric information; the model estimates confirm that differential incentives to internalize medical care offsets can explain disparities across plans. Counterfactuals show that strategic insurer incentives are as important as asymmetric information in determining benefit design.