We show how data from an evaluation in which subjects are randomly assigned to some treatment versus a control group can be combined with nonexperimental methods to estimate the differential effects of alternative treatments. We propose tests for the validity of these methods. We use these...

Estimation of average treatment effects under unconfounded or ignorable treatment assignment is often hampered by lack of overlap in the covariate distributions between treatment groups. This lack of overlap can lead to imprecise estimates, and can make commonly used estimators sensitive to the...

In this paper we develop two nonparametric tests of treatment effect heterogeneity. The first test is for the null hypothesis that the treatment has a zero average effect for all subpopulations defined by covariates. The second test is for the null hypothesis that the average effect conditional...

This chapter describes the intellectual development and the empirical implications of the literature on the economics of fertility as it applies to fertility behavior in developed economies. The chapter reviews the literature on dynamic models of fertility behavior over the parents' life cycle,...

A large body of theoretical work has explored the channels through which vertical contracts can induce efficiency improvements. However, it is also important to study vertical contracts empirically in order to gain insight into the relative size of different types of efficiency gains. In this...

"Theoretical investigations have examined both anti-competitive and efficiency-inducing rationales for vertical bundling, making empirical evidence important to understanding its welfare implications. We use an extensive dataset on full-line forcing contracts between movie distributors and video...