Essays on the Task Approach to Labor Markets

This dissertation consists of three essays on the task approach to labor markets. In the first chapter, I document that since 2000 the polarization of wages in the U.S. labor market stopped, as the wages of non-routine manual occupations fell in relative and absolute terms. I analyze the end of wage polarization through the lens of a dynamic general equilibrium model with occupation-biased technical change, human capital accumulation, and occupational mobility. I show that wage polarization ended because workers in non-routine manual occupations had lower initial human capital and lower human capital accumulation over time, and because after 2000 mobility across occupations fell, which magnified the differences in human capital accumulation across occupations. The second chapter estimates the effect of the import competition from China on the intensity of tasks performed by workers within U.S. manufacturing establishments between 2002 and 2017. I measure the changes in the intensity of these tasks by linking information on occupational employment from the Occupational Employment Statistics to the occupational characteristics from the Occupational Information Network (O*NET). I find that this “China shock” led establishments to significantly decrease the intensity of cognitive and interpersonal tasks, and to increase the intensity of manual and routine tasks. These estimations are consistent with US establishments reallocating employment to become more similar to their Chinese competitors and have important implications for the design of public policies. The third chapter explores the importance of changes in the intensity of tasks performed by workers to explain the evolution of wages. Despite changes in the workplace, the literature is based on the questionable assumption that the intensity of tasks remains constant over time. I harmonize and compare over time the intensity of non-routine cognitive, non-routine manual, interpersonal, and routine tasks in the Dictionary of Occupation Title (DOT) and the O*NET. I find the new fact that a sizable part of wage changes is due to increases in the return and the intensity of cognitive tasks. I show that this fact has implications for three well-documented wage trends during the last decades: wage polarization, increasing college premium, decreasing gender-wage gap.