This bit helped me to match lme results in R with SAS, try options(contrasts=c("contr.sum","contr.poly")) before lme model. -- View this message in context: http://r.789695.n4.nabble.com/Covariance-structure-for-lme-tp4630413p4635005.html Sent from the R help mailing list archive at Nabble.com.