The paper addresses mainly three questions. One, do workers tend to be employed by employers of the same ethnic group; two, what is the structure of the equilibrium wage contract, and three, do more ethnically homogeneous labor markets tend to have different labor contracts than more ethnically...

Heterogeneous firms facing demand-induced price fluctuations imperfectly compete for heterogeneous workers. It is shown that unemployment may arise in equilibrium because of the combination of uncertainty on product price and mismatch between workers’ skills and firms’ job requirements.

We propose a dynamic efficiency wage model with learning by doing. By taking into account the change inthe stock of workers’ knowledge, firms set efficiency wages such that the effort–wage elasticity is not in general equal to one.