Ex-ante moral hazard: empirical evidence for private health insurance in Brazil

Abstract This paper explores the existence of ex-ante moral hazard in private health insurance in Brazil. Before the advent of illness, insured individuals have no incentives to seek preventive care if it is not previously contractible. The data set comprises longitudinal administrative records of health care utilization from a Brazilian employer-sponsored health insurance plan. The empirical strategy is based on an exogenous and anticipated shock in health insurance coverage not associated with health conditions. The results show an increase of up to 17% on medical visits and 22% on diagnostic tests due to the loss of health insurance. Medical visits start to increase five months before the individual leaves the health insurance pool, reaching its peak at two months prior to exit. For diagnostic tests, the increase was observed only in the last two months before the loss of health insurance coverage