A central organizing framework of the voluminous recent literature studying changes in the returns to skills and the evolution of earnings inequality is what we refer to as the canonical model, which elegantly and powerfully operationalizes the supply and demand for skills by assuming two...

In this paper, we survey non-competitive theories of training. With competitive labor markets, firms never pay for investments in general training, whereas when labor markets are imperfect, firm-sponsored training arises as an equilibrium phenomenon. We discuss a variety of evidence which...