Health insurance and competition.

Summary Many countries have chosen to use market-based mechanisms to manage health risk. Although the diversity of regulations associated with them is important, the use of market mechanisms is currently an undeniable fact. The objective of this thesis is to analyze the arguments that justify the introduction of such mechanisms while the debate on public intervention in the health insurance sector remains open. In this respect, the first part of the thesis focuses on moral hazard behavior, the first chapter being devoted to ex ante moral hazard behavior while the second one deals with ex post moral hazard. In the second part, we propose hybrid forms of health risk management, located at the intersection of the two allocation modes mentioned. In chapter 3, we take up Diamond's position of organizing competition in the health insurance sector according to an auction procedure. We show that the presence of increasing returns to scale in the health insurance sector is not a sufficient condition for the different groups of insureds to be allocated to only one insurer. In chapter 4, we study the possibility of introducing fictitious competition between the local branches of a national public monopoly. We propose an estimate of the efficiency of health expenditure at the departmental level using the DEA econometric method. We show that health expenditure in some departments is abnormally high given the results obtained in terms of morbidity.