Three essays on Supplementary Health Insurance.

Summary This thesis deals with two questions relative to efficiency and fairness in mixed health insurance systems with partial mandatory coverage and voluntary supplementary health insurance (SHI): (i) the inflationary effect of SHI on medical prices. (ii) the fairness of SHI premiums. We set the analysis in the French context and perform empirical analyses on original individual-level data, collected from the administrative claims of a French insurer (MGEN). The sample is made of 99,878 individuals observed from 2010 to 2012. In Chapter 1, we estimate the causal impact of a generous SHI on patients' decisions to consult physicians who balance bill their patients. We find evidence that better coverage contributes to the rise in medical prices. In Chapter 2, we specify individual heterogeneity in moral hazard and consider its possible correlation with coverage choices. We find evidence of selection on moral hazard: individuals who are more likely to ask for coverage exhibit stronger moral hazard. In Chapter 3, results show that when SHI is voluntary, age-based premiums maximize transfers between low and high healthcare users but do not guarantee vertical equity.