Earnings Profile: Ability and Schooling: Comment.

The article presents comments of the author on the paper "Earning Profile: Ability and Schooling," by John Hause. Hause's paper is addressed to the perplexing matters of how to disentangle effects of ability and schooling on worker earnings and of the effect of ability on earnings over a worker's lifetime. His emphasis on "ability" and schooling as determinants of earnings is surely not intended to deny that other variables also affect earnings — or to deny that these other variables may also interact with ability and schooling level — but he barely touches on other variables or the possibility of interactions. Instead, Hause chooses to include in his regressions a variety of background variables, such as father's education, religion and marital status. The a priori relevance, however, of each of these variables to the problem at hand — the ability-schooling nexus — is by no means clear. When Hause examines the relationships between ability and earnings within schooling levels, he is estimating regression coefficients under the implicit assumption that other determinants of earnings are uncorrelated with the included ability, schooling level, and background variables.