Essays on migration and productivity[Essais sur les migrations et la productivité]

This dissertation explores the interaction between migration and productivity, through multiple angles, across three different countries and period contexts. Specifically, I study the labor market benefits of migrant mobility during an economic crisis, productivity gains due to migrant mobility in the reconstruction of a country in the aftermath of a war, and gains associated with a higher concentration of people in larger urban areas. I address these subjects both theoretically and empirically, using rich confidential social security data from Spain, Germany, and Turkey, applying a variety of panel data techniques and historical instruments to estimate causal relationships. The findings of these studies relate to many issues that interest both the academia and the policymakers yet on which little is known. This dissertation aims to contribute to knowledge gap on issues that will remain relevant foreseeable future.