Hello, I would like to verify my understanding of the kind of question for which MatchIt is a useful tool. My understanding is that one would use MatchIt if the focus of the research was the causal effect of the *treatment* variable. All other variables are control variables, and would be treated as such during the parametric analysis. In other words, one would not use MatchIt and then test for the explanatory power of the "control" variables. If MatchIt creates a dataset with perfect matches then the "control" variables should have no explanatory power. Perhaps this is obvious... I just wanted to check that I am not missing something. Thank you! -- Orsolya Lazar Department of Political Science University of Arizona Tucson, AZ 85721-0027 olazar(a)u.arizona.edu -- MatchIt mailing list served by Harvard-MIT Data Center List Address: matchit(a)lists.gking.harvard.edu Subscribe/Unsubscribe: http://lists.gking.harvard.edu/?info=matchit MatchIt Software and Documentation: http://gking.harvard.edu/matchit/