Dear posters, I have a question concerning binary data analysis. I have presence absence data of 5 sampling sessions within 3 years, of 12 fields. Each field had 12 traps. I would like to analyse the data with a Generalized Estimating Equations (GEE) Model in R. For the abundance data I used a gls with the function: correlation = corARMA(form = ~ session|trapfield, p = 1, q = 0) But now I want to use presence absence data?I know about the problem with correlated -binary data- but maybe somebody already created a solution? Something like that, which is not working?. rgee1 <- geeglm(Alus01 ~ treatment + scale(LAI) + scale(log(Tot_Sp)) + scale(AveH) , data = plates, family = binomial, waves = session, id trapfield, corstr = "ar1") Any help is appreciated a lot?. Thanks Yvonne -- View this message in context: http://r.789695.n4.nabble.com/binary-data-with-correlation-tp3393884p3393884.html Sent from the R help mailing list archive at Nabble.com.