We use the control function approach to identify the average treatment effect and the effect of treatment on the treated in models with a continuous endogenous regressor whose impact is heterogeneous. We assume a stochastic polynomial restriction on the form of the heterogeneity but, unlike...

This paper considers two problems that arise in determining the role of ability in explaining the level of and change in the rate of return to schooling. (1) Ability and schooling are so strongly dependent that it is not possible, over a wide range of variation in schooling and ability, to...

This paper presents new evidence from the NLSY on the importance of meritocracy in American society. In it, we find that general intelligence, or g -- a measure of cognitive ability--is dominant in explaining test score variance. The weights assigned to tests by g are similar for all major...

This paper examines the contribution of the rise in the return to ability to the rise in the economic return to education. All of the evidence on this question comes from panel data sets in which a small collection of adjacent birth cohorts is followed over time. The structure of the data...

In The Bell Curve, Herrnstein and Murray argue that the U.S. economy is a meritocracy in which differences in wages (including differences across race and gender) are explained by differences in cognitive ability. In this paper we test their claim for wages conditional on occupation using a...

This paper examines the properties of instrumental variables (IV) applied to models with essential heterogeneity, that is, models where responses to interventions are heterogeneous and agents adopt treatments (participate in programs) with at least partial knowledge of their idiosyncratic...

This paper uses the marginal treatment effect (MTE) to unify the nonparametric literature on treatment effects with the econometric literature on structural estimation using a nonparametric analog of a policy invariant parameter; to generate a variety of treatment effects from a common...

This paper develops methods for evaluating marginal policy changes. We characterize how the effects of marginal policy changes depend on the direction of the policy change, and show that marginal policy effects are fundamentally easier to identify and to estimate than conventional treatment...

This paper derives simply computed closed-form expressions for the Average Treatment Effect (ATE), the effect of Treatment on the Treated (TT), Local Average Treatment Effect (LATE) and Marginal Treatment Effect (MTE) in a latent variable framework for both normal and non-normal models. The...

This paper estimates the marginal returns to college for individuals induced to enroll in college by different marginal policy changes. The recent instrumental variables literature seeks to estimate this parameter, but in general it does so only under strong assumptions that are tested and found...