The task is an analysis of the traditional labor supply model using several competing methodologies. The approach is a step-by-step exploration of alternative labor supply estimating equations that attempts to identify the independent (marginal) effect of each particular change in the form of these equations. By systematically exploring what difference each of these changes makes to the parameter estimates, one can isolate which factors strongly affect estimated response parameters. Results from existing research can then be evaluated within a larger context, and future research can concentrate on resolving those methodological issues that do make a difference.

This article examines past evaluations of government training programs for the economically disadvantaged and offers an agenda for future research. It is found that government training programs are producing modest increases in earnings for adult men and women, but are probably not producing positive effects for youth. Future research must better document links between program-provided training and acquisition of valuable skills and must explore potential returns from increased scale. The recent adoption of random assignment has improved the accuracy of field evaluations but would benefit from an economic theory of evaluation to guide research into increasing training effectiveness.