Myopia, Price Perception, and Moral Hazard in Health Insurance
Job Market Paper
I show that spending responses to cost sharing in health insurance depend not only on contractual incentives but also on household myopia and price perception. Using administrative claims data from a large employer plan, I study a natural experiment that introduced a deductible and raised the out-of-pocket maximum. Households on average reduce spending modestly, but the reduction rises steeply with baseline health risk and is concentrated among the highest-risk households. Because high-risk households should readily anticipate reaching the out-of-pocket maximum under either contract, a structurally estimated forward-looking model predicts that they respond least, contrary to the observed risk gradient. To resolve this puzzle, I develop and estimate the first structural model of moral hazard that jointly incorporates household myopia and imperfect spot-price perception. In the model, myopic households respond to spot prices inferred from medical bills, with two frictions biasing perceived spot prices upward: (1) bills arrive with delays, causing price beliefs to lag behind actual prices, and (2) households may infer the price of subsequent care from the average price on a bill rather than the marginal price. I provide evidence for both mechanisms using administrative data and an incentivized survey experiment. The estimated model matches the modest aggregate response and captures the steep risk gradient that the forward-looking model cannot. More broadly, the model provides a framework for understanding spending responses under nonlinear health insurance contracts when households learn their spot prices gradually and imperfectly.


