Hi, I?d like to do some sample matching with propensity scores. I?ve estimated the propensity scores: glm1 <- glm(Exposed~Gender+ImagingCentreID+espad.3a+drinks.preg+espad.6+audit.total+ PDS.all, family=binomial, data=PBQ_110421) Now I would like to match on the propensity score and have an exact match on Gender and ImagingCentreID. How do I specify this in the command: M1 <-Match(Tr = Exposed, X = glm1$fitted) ? Sorry, if my question is trivial! But I am an absolute beginner in R. Thanks, Kathrin - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Kathrin M?ller, Dipl.-Psych. PhD Student Technische Universit?t Dresden Faculty of Medicine Carl Gustav Carus Department of Psychiatry and Psychotherapy Section of Systems Neuroscience W?rzburger Str. 35 01187 Dresden Germany Phone: +49 (351) 463-42208 Fax: +49 (351) 463-42202 E-Mail: kathrin.mueller at tu-dresden.de