The classic theory of moral hazard concerns the insurance of a single good and predicts that co-insurance is larger when the elasticity of demand is higher and when small risks are insured. We extend this analysis to the insurance of multiple goods; for example, the simultaneous insurance of...

Moral hazard and adverse selection create inefficiencies in private health insurance markets and understanding the relative importance of each factor is critical for policy. We use claims data from a large firm to isolate moral hazard from plan selection. Previous studies have attempted to...