TY - JOUR AU - Graham,Bryan S. AU - Pinto,Cristine Campos de Xavier AU - Egel,Daniel TI - Efficient Estimation of Data Combination Models by the Method of Auxiliary-to-Study Tilting (AST) JF - National Bureau of Economic Research Working Paper Series VL - No. 16928 PY - 2011 Y2 - April 2011 UR - http://www.nber.org/papers/w16928 L1 - http://www.nber.org/papers/w16928.pdf N1 - Author contact info: Bryan S. Graham University of California - Berkeley 508-1 Evans Hall #3880 Berkeley, CA 94720-3880 Tel: (510) 642 4752 E-Mail: bgraham@econ.berkeley.edu Cristine Campos de Xavier Pinto Escola de Economia de São Paulo, FGV/SP Rua Itapeva 474, sala 1200 São Paulo– SP, Brasil, 01332-000 E-Mail: cristinepinto@gmail.com Daniel Egel Institute on Global Conflict and Cooperation (IGCC University of California - San Diego 9500 Gilman Drive, MC 0518 La Jolla, CA 92093-0518 E-Mail: degel@ucsd.edu AB - We propose a locally efficient, doubly robust, estimator for a class of semiparametric data combination problems. A leading estimand in this class is the average treatment effect on the treated (ATT). Data combination problems are related to, but distinct from, the class of missing data problems analyzed by Robins, Rotnitzky and Zhao (1994) (of which the Average Treatment Effect (ATE) estimand is a special case). Our procedure may be used to efficiently estimate, among other objects, the ATT, the two-sample instrumental variables model (TSIV), counterfactual distributions, and poverty maps. In an empirical application we use our procedure to characterize residual Black-White wage inequality after flexibly controlling for 'pre-market' differences in measured cognitive achievement as in Neal and Johnson (1996). We find that residual Black-White inequality is negligible at lower and higher quantiles of the Black wage distribution, but substantial at middle quantiles. ER -