Most health insurance uses cost-sharing to reduce excess utilization. Supplemental insurance can blunt the impact of this cost-sharing, increasing utilization and exerting a negative externality on the primary insurer. This paper estimates the effect of private Medigap supplemental insurance on...

Most health insurance uses cost-sharing to reduce excess utilization. Supplemental insurance can blunt the impact of this cost-sharing, increasing utilization and exerting a negative externality on the primary insurer. This paper estimates the effect of private Medigap supplemental insurance on...

The welfare associated with public insurance is often difficult to quantify. Relative to private insurance, a fundamental difficulty is that public insurance is typically compulsory, so the demand for coverage is unobserved and thus cannot be used to analyze welfare. However, in many public...