Hi, I have a question about how to recreate matched groups once I transfer the data from R into another statistical program (such as SPSS). I don't have a problem doing so if I use 1:1 matching, however, when I match with replacement or use 2:1 matching (where there are not the same number of treated and control cases), the means of the covariates for the treated and control groups do not come out to be the same as they were in the summary data in R. I understand that this has something to do with the "weights" variable, but I'm not sure how to incorporate this so that I can recreate the same matched samples. Any help you can provide would be greatly appreciated! Thanks! Kerry Kerry Richmond Department of Criminology and Criminal Justice University of Maryland, College Park -- 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/