Substitutes for Success? Public Versus Private Competition in Medicare Advantage
研究了医疗保险优势计划中公共选项（传统医疗保险）与私人保险公司之间的竞争如何影响受益人福利，发现传统医疗保险的竞争作用减弱，而私人市场竞争加剧但主要由大型全国性保险公司主导，存在市场壁垒问题。
We assess the evolving role of competition in Medicare Advantage and its implications for beneficiary welfare. We describe how competition from the public option, traditional Medicare, and other private insurers within Medicare Advantage act as substitutes in incentivizing plans to deliver value. We show that while historically the choice between traditional Medicare and Medicare Advantage provided a vital competitive dynamic, traditional Medicare's strength as a competitor has declined significantly, driven by generous payments favoring private plans. Consequently, the burden of ensuring value for enrollees has shifted to competition within the Medicare Advantage market. While county-level competition among private insurers has increased, this growth is primarily driven by the expansion of large national carriers rather than new entrants. Insurers still wield substantial market power due to significant barriers to entry, raising concerns about the ability of the program to incentivize private insurers to use public dollars to maximize value for beneficiaries.