To combat adverse selection, governments increasingly base payments to health plans and providers on enrollees' scores from risk-adjustment formulae. In 2004, Medicare began to risk-adjust capitation payments to private Medicare Advantage (MA) plans to reduce selection-driven overpayments. But...

We examine whether and to what extent consolidation in the US health insurance industry has contributed to higher employer-sponsored insurance premiums. We exploit the differential impact across local markets of a national merger of two insurers to identify the causal effect of concentration on...

Medicare Part D began coverage of prescription drugs in 2006. Rather than setting pharmaceutical prices, the government contracted with private insurers to provide drug coverage. Theory suggests that additional insured consumers will raise the optimal price of a branded drug, while the insurer's...