Hi, I would like to fit a GLM model with GEE on clustered data. I tried to use gee in the GEE package on a twin data set. All cluster are of size 2. I removed the missing data and ordered by IDENTIF2 first.
library(gee) mod.pc <- gee(Y ~ X1 + X2 , id = IDENTIF2, family = binomial, corstr = "unstructured", data = na.omit(df)) gives the following result : Beginning Cgee S-function, @(#) geeformula.q 4.13 98/01/27 running glm to get initial regression estimate (Intercept) X1M X2Sans AMP X2Stim -2.7756284 0.4658861 -1.6508288 -1.5059518 Erreur dans gee(Y ~ X1 + X2, id = IDENTIF2, family = binomial, corstr = "unstructured", : NA/NaN/Inf dans un appel à une fonction externe (argument 2) # meaning in a call to an external function De plus : Warning message: In gee(Y ~ X1 + X2, id = IDENTIF2, family = binomial, corstr = "unstructured", : NAs introduits lors de la conversion automatique # meaning NAs introduced during the automatic conversion The regression gives results with SAS version 8 on the same dataset (results are pretty close from the results of a naive logistic regression). I tried to change the explanatory variables (X1 alone, X2 alone, other possible explanatory variables : no result). I do not find where the error comes from. Should I trust the results from SAS ? Thank you for your help. David Using R2.7.2 and gee version 4.13-13 PS Naive logistic regression give similar results on R and SAS in my case ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
