The Oaxaca-Blinder Unexplained Component as a Treatment Effects Estimator

Abstract

In this paper I use the National Supported Work (NSW) data to examine the finite-sample performance of the Oaxaca-Blinder unexplained component as an estimator of the population average treatment effect on the treated (PATT). Precisely, I follow sample and variable selections from Dehejia and Wahba (1999), and conclude that Oaxaca-Blinder performs better than any of the estimators in this influential paper, provided that overlap is imposed. As a robustness check, I consider alternative sample (Smith and Todd, 2005) and variable (Abadie and Imbens, 2011) selections, and present a simulation study which is also based on the NSW data.