Regulation of Insurance with Adverse Selection and Switching Costs: Evidence from Medicare Part D.
I take advantage of regulatory and pricing dynamics in Medicare Part D to empirically explore interactions among adverse selection, switching costs, and regulation. I first document novel evidence of adverse selection and switching costs within Part D using detailed administrative data. I then estimate a contract choice and pricing model in order to quantify the importance of switching costs for risk-sorting, and for policies that may affect risk sorting. I first find that in Part D, switching costs help sustain an adversely-selected equilibrium and are likely to mute the ability of ACA policies to improve risk allocation across contracts, leading to higher premiums for some enrollees. I then estimate that, overall, decreasing the cost of active decision-making in the Part D environment could lead to a substantial gain in consumer surplus of on average $400-$600 per capita, which is around 20%-30% of average annual per capita drug spending.
Published Versions
Maria Polyakova, 2016. "Regulation of Insurance with Adverse Selection and Switching Costs: Evidence from Medicare Part D," American Economic Journal: Applied Economics, American Economic Association, vol. 8(3), pages 165-95, July. citation courtesy of 
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