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...

Although surveys show that traditional ordering of average wages--i.e. higher earnings with higher schooling and concave age-wage profiles--have not changed during the past three decades, the actual size of the wage differentials measured by education or by work experience has varied from peak...