Paying more for less? Insurer competition and health plan generosity in the Medicare Advantage program

This paper explores the relationship between insurer competition and health plan benefit generosity by examining the impact of a regulatory change that caused the cancellation of 40% of the private plans in Medicare. I isolate cancellation's causal effect by using variation induced by insurers canceling all plans nationally. Results show that insurers in markets affected by cancellation reduced the benefit generosity of the plans remaining in the market. In the average market, out-of-pocket costs for a representative beneficiary enrolled in plans not directly affected by the policy increased by $91 annually. In the least competitive markets, out-of-pocket costs increased by roughly $64-$127 a year for enrollees in those plans. Meanwhile in the most competitive markets, benefit generosity barely changed. These findings have crucial implications for markets such as health insurance exchanges, as they suggest that plan generosity is degraded when competition declines.