I apply Ricardo’s principle of comparative advantage to a theory of factor substitutability in a model with a continuum of worker and job types. Highly skilled workers have a comparative advantage in complex jobs. The model satisfies the distance-dependent elasticity of substitution (DIDES)...

When types of workers are imperfect substitutes, the Mincerian rate to return to human capital is negatively related to the supply of human capital. We work out a simple model for the joint evolution of output and wage dispersion. We estimate this model using cross-country panel data on GDP and...

A wide class of models with On-the-Job Search (OJS) predicts that workers gradually select into better-paying jobs. We develop a simple methodology to test predictions implied by OJS using two sources of identification: (i) time-variation in job-finding rates and (ii) the time since the last...