What Drove First-Year Premiums in Stand-Alone Prescription Drug Insurance?
Medicare’s Part D offers heavily subsidized new drug coverage to 22.5 million seniors to date, of whom 16.5 million are in stand-alone drug plans (Department of Health and Human Services, 2006). The government delegated the delivery of the benefit to private insurance companies arguing that market incentives would lead them to provide coverage at the lowest price possible. The massive entry of plans and the large variety of actuarial designs and formularies offered make it complicated to assess how insurers set premiums during this first year of the program. This paper presents the first econometric evidence on whether premiums in the stand-alone drug plan markets are driven by the relevant factors predicted by insurance theory. Using data gathered from the Centers for Medicare and Medicaid Ser-vices, we measure a plan’s generosity as the simulated out of pocket payments for different sets of drugs. We also identify the listed full drug prices by each insurer and merge these with other
