Abstract
I estimate a Bayesian persuasion model to examine how financial incentives and asymmetric information shape physician–patient interactions. This approach offers new insights into the role of insurance. First, the model predicts that patients' coinsurance moderates physicians' responsiveness to increases in service fees. This prediction is supported by a difference‐in‐differences analysis using Chinese health insurance claims data with random variation in physicians' reimbursement and patients' coinsurance rates. Second, the model implies that lower coinsurance rates reduce both patient price elasticity and skepticism, increasing the likelihood of physicians misdirecting patients toward unnecessary treatments. Using structural model estimates, I show that for a diagnosis where surgical treatment is discretionary, nearly half of the patients who received surgery would not have done so were they fully informed. Such misdirection from physicians is greater when coinsurance rates decrease, highlighting a new inefficiency channel beyond moral hazard. I decompose the effect of lowering coinsurance into moral hazard and the novel greater misdirection effect. Counterfactual analysis shows that, while patients benefit from lower out‐of‐pocket costs, greater misdirection nearly offsets these welfare gains.