Hirano, Keisuke; Imbens, Guido W.; Ridder, Geert - In: Econometrica 71 (2003) 4, pp. 1161-1189
We are interested in estimating the average effect of a binary treatment on a scalar outcome. If assignment to the treatment is exogenous or unconfounded, that is, independent of the potential outcomes given covariates, biases associated with simple treatment-control average comparisons can be...