This paper provides a method for linearly combining skill classes so that the number of classes required to describe a skill distribution is minimized. The principal analytical device is that of distinguishing between skill classes and the characteristics of persons in a class. The distinction...

The "human capital earnings function," in which earnings are expressed as a quadratic in potential experience, is probably the most widely accepted empirical specification in economics. In spite of its widespread acceptance, the human capital earnings function provides a very poor approximation...

During the last twenty-five years, annual hours worked by prime aged men fell by the equivalent of six forty-hour workweeks. The reduction was more pronounced among those younger than among mid-age workers, among black men than among white men, and among those with less schooling. Thus hours...