Regulation of Insurance with Adverse Selection and Switching Costs: Evidence from Medicare Part D
利用联邦医疗保险D部分的监管和定价动态，研究逆向选择、惯性（转换成本）与监管之间的相互作用，发现转换成本有助于维持逆向选择均衡，而主动决策可带来人均每年400-600美元的消费者剩余增加。
I take advantage of regulatory and pricing dynamics in Medicare Part D to explore interactions among adverse selection, inertia, and regulation. I first document novel evidence of adverse selection and switching frictions within Part D using detailed administrative data. I then estimate a contract choice and pricing model that quantifies the importance of inertia for risk sorting. I find that in Part D switching costs help sustain an adversely-selected equilibrium. I also estimate that active decision making in the existing policy environment could lead to a substantial gain in annual consumer surplus of on average $400–$600 per capita—20 percent to 30 percent of average annual spending.