Moral hazard and consumer incentives in health care

Consumer incentives are reflected in a wide range of choices, many of which occur in both insurance- and tax-financed health care systems. However, health insurance and sick leave pay cause consumer incentives to be reflected in moral hazard effects of several types. Theoretically, ex ante moral hazard (a reduction of preventive effort in response to insurance coverage) is not unambiguously predicted, and there is very limited empirical evidence about it. The case for static ex post moral hazard (an increase in the demand for medical care of a given technology) is stronger. The empirical evidence reported comes from three sources, natural experiments, observational comparisons of individuals, and the Health Insurance Experiment (HIE). The distinguishing feature of the HIE is that participants were assigned to insurance plans, which forestalls the possibility of good risks self-selecting plans with substantial cost sharing, resulting in an overestimate of the effects of plan design on health care expenditure. While the values of estimated price elasticities vary widely among the three sources and less markedly according to the type of care (outpatient, hospital, dental, mental), the responsiveness of the demand for medical care to net price is beyond doubt. The pure price elasticity for medical care in excess of a deductible (i.e. where the marginal price is constant) was estimated by HIE at -0.2 overall. Finally, there may be a dynamic moral hazard effect (choice biased in favor of new, usually more expensive medical technology). Here, the empirical evidence is very scanty again. Another promising field for future research is the interplay between consumer incentives and rationing by the physician in managed care.