Roger Bivand Roger.Bivand at nhh.no writes:>This was exactly why I emphasised care. One way to try to do this is > to extract the FS data slot: > FSd <- as(FS, "data.frame") > and then merge() FSd and agg2, using - untried - something like: > FS1d <- merge(FSd, agg2, by="row.names", all=TRUE)It worked after I added one more step: row.names(FS1d) <- FS1d$SUBJECT Thanks! Aleksandr Andreev Duke University