Hi, I already have matched samples, which were matched using different software. I need to calculate Abadie-Imbens standard errors, together with the average treatment effect. I know that the Matching package enables me to calculate these after a Matching procedure, but is there any way to do it on already matched samples, which were not produce by the Match function? Many thanks, Louise. -- View this message in context: http://r.789695.n4.nabble.com/Var-calc-in-Matching-tp3666950p3666950.html Sent from the R help mailing list archive at Nabble.com.