Essays on labor market frictions.

Summary This thesis studies the frictions that alter the matching processes between labor supply and demand. The matching of aggregate labor supply and demand partly explains employment and wage levels. However, imbalances remain in many labor markets. Despite radical changes such as globalization and the digitalization of job search, these imbalances persist. This thesis is therefore organized around two axes studying the frictions associated with these two important phenomena. The first axis is dedicated to the globalization of the labor market and foreign workers. The first two chapters of this thesis are devoted to this. The first chapter focuses on a friction affecting foreign workers in Germany. It documents how cultural differences with their country of origin lead to a penalty on their wages. The second chapter examines a friction related to employers. It documents the difficulties of American employers in recruiting domestic workers for jobs associated with new technologies. It thus explains, in part, why these employers seek to recruit foreign workers. The second section of the thesis is dedicated to the digitalization of the labor market. The third chapter explores an information friction emanating from the digitalization of the job search. It quantifies the share of obsolete ads online on three of the major US job boards. Thus, it documents a negative externality wasting job seekers' search time and effort.