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...

Most existing studies of risk selection in the employer-sponsored health insurance market are case studies of a single employer or of an employer coalition in a single market. We examine risk selection in the employer-sponsored market by applying a switcher' methodology to a national, panel data...

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...

A positive correlation between insurance coverage and ex post risk can be an indicator for private information in insurance markets. However, this test fails if agents have heterogeneous risk attitudes. We propose a new test that conditions on unobserved types of individuals who differ in their...

We present a graphical framework for analyzing both theoretical and empirical work on selection in insurance markets. We begin by using this framework to review the "textbook" adverse selection environment and its implications for insurance allocation, social welfare, and public policy. We then...

We describe recent advances in the empirical analysis of insurance markets. This new research proposes ways to estimate individual demand for insurance and the relationship between prices and insurer costs in the presence of adverse and advantageous selection. We discuss how these models permit...

This paper derives a portfolio diversification rationale for a trade policy regime that insures returns to nondiversifiable human capital investment. In the absence of complete insurance markets for human capital, the decentralized equilibrium is characterized by excessive specialization. The...

A large empirical literature found that the correlation between insurance purchase and ex post realization of risk is often statistically insignificant or negative. This is inconsistent with the predictions from the classic models of insurance a la Akerlof (1970), Pauly (1974) and Rothschild and...

Standard policies to correct market power and selection can be misguided when these two forces co-exist. Using a calibrated model of employer-sponsored health insurance, we show that the risk adjustment commonly used by employers to offset adverse selection often reduces the amount of...

The willingness to pay for insurance captures the value of insurance against only the risk that remains when choices are observed. This paper develops tools to measure the ex-ante expected utility impact of insurance subsidies and mandates when choices are observed after some insurable...