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 validity of the Oaxaca–Blinder unexplained component as an estimator of the population average treatment effect on the treated (PATT). Precisely, I utilize dataset and variable selections used in previous studies of the NSW data to compare the performance of the Oaxaca–Blinder unexplained component with methods based on the propensity score (Dehejia and Wahba, 1999) and bias-corrected matching estimators (Abadie and Imbens, 2011). I show that in both cases the Oaxaca–Blinder unexplained component performs superior compared to the previously analyzed estimators provided that common support is imposed.