Quality Ratings and Premiums in the Medicare Advantage Market

Abstract

We examine the response of Medicare Advantage contracts to published quality ratings. We identify the effect of star ratings on premiums using a regression discontinuity design that exploits plausibly random variation around rating thresholds. We find that 3, 3.5, and 4-star contracts in 2009 significantly increased their 2010 monthly premiums by $20 or more relative to contracts just below the respective threshold values. High quality contracts also disproportionately dropped $0 premium plans or expanded their offering of positive premium plans. Welfare results suggest that the estimated premium increases reduced consumer welfare by over $250 million among the affected beneficiaries.

Keywords: Medicare Advantage, premiums, quality ratings, regression discontinuity

JEL Classification: D21, D43, Ill, C51