This paper considers the problem of policy evaluation in a modern society with heterogeneous agents and diverse groups with conflicting interests. Several different approaches to the policy evaluation problem are compared including the approach adopted in modern welfare economics, the classical...

In recent years, the study of labor supply has occupied the attention of a large number of economists. With the growth in interest in the topic and with the inevitable diversity of economic models and statistical methods proposed by new entrants in the field, the literature has developed its own...

This paper compares the structural approach to economic policy analysis with the program evaluation approach. It offers a third way to do policy analysis that combines the best features of both approaches. We illustrate the value of this alternative approach by making the implicit economics of...

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 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 formulates and estimates an open-economy overlapping generation general-equilibrium model of endogenous heterogeneous human capital in the form of schooling and on-the-job training. Physical capital accumulation is also analyzed. We use the model to explain rising wage inequality in...

This paper defines and estimates general equilibrium treatment effects. The conventional approach in the literature on treatment effects ignores interactions among individuals induced by the policy interventions being studied. Focusing on the impact of tuition policy, and using estimates from...

This paper develops and estimates an overlapping generations general equilibrium model of labor earnings, skill formation and physical capital accumulation with heterogeneous human capital. The model analyzes both schooling choices and post-school on-the-job investment in skills in a framework...

This paper considers the use of instrumental variables to estimate the mean effect of treatment on the treated. It reviews previous work on this topic by Heckman and Robb (1985, 1986) and demonstrates that (a) unless the effect of treatment is the same for everyone (conditional on observables),...

This paper considers the recent case for randomized social experimentation and contrasts it with older cases for social experimentation. The recent case eschews behavioral models, assumes that certain mean differences in outcomes are the parameters of interest to evaluators and assumes that...