Joseph Hnath

Dissertation Title: "Competition and Regulation in Medicare Advantage"

This dissertation examines how managed competition functions in the Medicare Advantage (MA) program through three empirical studies. The first paper evaluates the causal effect of default enrollment policies on plan enrollment choice and health care utilization for low-income dual-eligible beneficiaries. The second paper describes how national MA insurance carriers have expanded market share between 2012 and 2023, primarily by acquiring smaller regional carriers; it also identifies a relatively low threshold of MA penetration above which further market growth is no longer associated with local market concentration. The third paper evaluates the causal effect of competitor entry on MA plan bids and rebates, where mixed empirical evidence suggests that the current levels of competitive pressure may be inadequate. Together, the three papers study the demand-side defaults, supply-side concentration, and competitive entry dynamics of the Medicare Advantage program, finding that the current architecture of managed competition has room for improvement with more sophisticated and evidence- driven regulatory policy reforms.