Health plans for the poor increasingly limit access to specialty hospitals. We investigate the role of adverse selection in generating this equilibrium among private plans in Medicaid. Studying a network change, we find that covering a top cancer hospital causes severe adverse selection,...

Exploiting random assignment of Medicaid beneficiaries to managed care plans, we identify plan-specific effects on healthcare utilization. Auto-assignment to the lowest-spending plan generates 30% lower spending than if the same enrollee were assigned to the highest-spending plan, despite...

Medicaid, the government program for providing health insurance to low-income and disabled Americans, is the largest health insurer in the United States with more than 73 million enrollees. It is also the sector of the U.S. public health insurance system that relies most heavily on the tools of...

The Affordable Care Act Marketplaces were introduced in 2014 as part of a reform of the U.S. individual health insurance market. While the individual market represents a small slice of the U.S. population, it has historically been the market segment with the lowest rates of take-up and greatest...

Insurance markets often feature consumer sorting along both an extensive margin (whether to buy) and an intensive margin (which plan to buy). We present a new graphical theoretical framework that extends the workhorse model to incorporate both selection margins simultaneously. A key insight from...

In this essay, we review the theory and evidence concerning selection in competitive health insurance markets and discuss the common policy tools used to address the problems it creates. We begin by outlining some important but often misunderstood differences between two types of conceptual...

Some consumers lack the cash needed to pay for medical care. As a result, they either delay care until they can pay for it or they forgo the care altogether. To test for such a possibility, we study the distribution of monthly Social Security checks among Medicare Part D enrollees. When Social...

The conventional method for developing health care plan payment systems uses existing data to study alternative algorithms with the purpose of creating incentives for an efficient and fair health care system. In this paper, we take a different approach and modify the input data rather than the...

Health insurance markets face two forms of adverse selection problems. On the demand side, adverse selection leads to plan price distortions and inefficient sorting of consumers across health plans. On the supply side, adverse selection creates incentives for plans to inefficiently distort...

Risk adjustment of payments to health plans is fundamental to regulated competition among private insurers, which serves as the basis of national health policy in many countries. To date, estimation and evaluation of a risk adjustment model has been a two-step process. In a first step, the...