Labor market exclusion in matching models.

Summary This thesis analyzes the determinants of exclusion from the labor market. It focuses on the mechanisms of exclusion centered on the unemployability of excluded workers. Three principles guide the reflection: exclusion is a facet of unemployment, individual employability is relative, and the heterogeneity of the workforce is endogenous. The first chapter analyzes the phenomena of discrimination through the prism of the negative time dependence of unemployment exit risks. We distinguish within a unified framework four arguments put forward in the literature: ex ante heterogeneity, the signal related to the duration of unemployment, the demoralization of the long-term unemployed, and the loss of human capital related to the unemployment episode. Chapters 2 and 3 examine a strategic exclusion mechanism. Chapter 2 focuses on the exclusion of low-skilled workers . Chapter 3 on the exclusion of the long-term unemployed. In chapters 4 and 5, the number of firms is endogenous and individuals lose human capital during episodes of unemployment. Chapter 4 focuses on the nature of the training provided by firms, and on the mode of wage bargaining. In chapter 5, aging causes relative losses of human capital. The endogenous growth rate of productivity determines the rate of obsolescence of individual skills. This mechanism leads to the exclusion of older unemployed workers.