A model of growth is developed in which finite-lived individuals invest in human capital, investments have a positive external effect on the human capital of later cohorts, and labor with more human capital produces higher-quality goods. Stationary growth paths are analyzed, paths along which human capital and the quality of goods grow at a common, constant rate. It is also shown that if a small open economy is either very advanced or very backward relative to the rest of the world, then its rate of investment in human capital is lower under free trade than under autarky.

Observed human capital explains less than half of wage variation. In BLS Industry Wage Surveys, establishment-based wage differentials (controlling for occupation) account for 20–70 percent of intra-industry wage variation. This corresponds to a standard deviation in wages of 14 percent of the mean, almost as large as interindustry wage variation. Investigation suggests that establishment wage differentials are not random variations or returns to usual measures of human capital.

James B. Rebitzer, Lowell J. Taylor; A Model of Dual Labor Markets When Product Demand Is Uncertain*, The Quarterly Journal of Economics, Volume 106, Issue 4, 1

This paper uses job applications data to investigate the relationship between job queues and wage differentials. The main finding is that openings for jobs that pay the minimum wage attract more job applicants than jobs that pay either slightly more or slightly less than the minimum wage. This spike in the job application rate distribution suggests that ex ante rents generated for employees by an above market-level minimum wage are not completely dissipated by reductions in nonwage benefits. In addition, we find that highly unionized firms, large firms, and firms in high-wage industries tend to receive relatively many job applicants for openings.