Supplemental Health Insurance and Healthcare Consumption—A Dynamic Approach to Moral Hazard

We analyze the existence and persistence of moral hazard over time to test the assumption of pent-up demand. We consider the effects of supplemental health insurance provided by a private insurer when added to compulsory public insurance already supplemented by private insurance. Using panel data from a French mutuelle, we compute error component models with the Chamberlain specification to control for adverse selection. By separating outpatient care consumption into (1) the probability of healthcare use, (2) the number of uses conditional on use and (3) the per-unit cost of care, we provide evidence that supplemental insurance is significantly and positively associated with (1), (2) and (3). However, these effects decrease significantly over time. This pattern supports the existence of pent-up demand, the magnitude of which varies greatly and depends on the dimensions (1), (2) and (3) and the type of care (physician care, prescription drugs, dental care or optical care).