This paper proposes a nonparametric method of estimating marginal treatment effects in heterogeneous populations. Building upon an insight of Heckman and Vytlacil, the conventional treatment effects model with heterogeneous effects is shown to imply that outcomes are a nonlinear function of...

This volume collects a series of essays by prominent economists on each of the major means-tested, or welfare, programs in the United States: the Medicaid, Earned Income Tax Credit, Supplemental Nutrition Assistance, Temporary Assistance for Needy Families, Supplemental Security Income,...