Estimation of average treatment effects under unconfoundedness or exogenous treatment assignment is often hampered by lack of overlap in the covariate distributions. This lack of overlap can lead to imprecise estimates and can make commonly used estimators sensitive to the choice of...

A large part of the recent literature on program evaluation has focused on estimation of the average effect of the treatment under assumptions of unconfoundedness or ignorability following the seminal work by Rubin (1974) and Rosenbaum and Rubin (1983). In many cases however, researchers are...

Using a new firm-level dataset that includes explicit information on referrals by current employees, we investigate the hiring process and the relationships among referrals, match quality, wage trajectories and turnover for a single U.S. corporation, and test various predictions of theoretical...