Crump, Richard K.; Hotz, V. Joseph; Imbens, Guido W.; … - In: The Review of Economics and Statistics 90 (2008) 3, pp. 389-405
In this paper we develop two nonparametric tests of treatment effect heterogeneity. The first test is for the null hypothesis that the treatment has a zero average effect for all subpopulations defined by covariates. The second test is for the null hypothesis that the average effect conditional...