Double Coverage and Demand for Health Care : Evidence from Quantile Regression

An individual experiences double coverage when he benefits from more than one health insurance plan at the same time. This paper examines the impact of such supplementary insurance on the demand for health care services. Its novelty is that within the context of count data modelling and without imposing restrictive parametric assumptions, the analysis is carried out for different points of the conditional distribution, not only for its mean location. Results indicate that moral hazard is present across the whole outcome distribution for both public and private second layers of health insurance coverage but with greater magnitude in the latter group. By looking at different points we unveil that double coverage effects are smaller for high levels of usage. We use data for Portugal on the consumption of doctor visits, taking advantage of particular features of the public and private protection schemes on top of the statutory National Health Service