Earnings, occupation, and human capital investment

In recent years the human capital earnings model has been widely used as a framework for examining the determination fearnings. A spec-ification of the human capital earnings function developed by Chiswick and Mincer has been em-ployed to examine arnings determination across individuals [Mincer, 1974b], states [Chiswick, 1974], metropolitan areas [Hirsch, 1978], oc-cupations [Rahm, 1971], and over time [Chis-wick-Mincer, 1972]. However, empirical stud-ies utilizing the human capital framework have assumed that he effects of workexperience (post-school investment) on earnings are identical for individuals, regardless of occupation. This assumption runs counter to the current emphasis of many labor economists on the im-portance to lifetime earnings of gaining early ac-cess to certain occupational job ladders and of receiving firm specific on-the-job training [Doer-inger and Piore, 1971; Thurow, 1975]. Likewise, human capital economists stress the importance of postschool training investments and at least recognize the fact that these investments vary across occupations. Indeed, Mincer has stated that [Mincer, 1974a, p. 33]: "an analysis n which these ffects [of schooling and of experience] are allowed to differ [across occupations] would be desirable for a number of purposes, not the least ofwhich is an insight in-to differential post-school job skill investments." This paper examines whether schooling, ex-perience, and weeks worked have different ef-fects on individual earnings in nine separate oc-cupational categories. The Chiswick-Mincer spec-*University of North Carolina at Greensboro. Th