I am sorry to bother the group with what is probably a simple error on my behalf as I am new to R, but I have been able to find a solution looking online or in the R forums. I have just started using R so I can use the catmap package which allows a meta analysis of both case control and TDT studies. I am using the latest windows version of R (v 2.12) and the latest version of catmap (V1.6). I can perform the actual meta analysis at the heart of catmap; e.g.catmap('rs2305764.txt', 0.95, TRUE, TRUE) works fine, giving me all the expected outputs and a tabulation of the ORs and CIs for each study. But when I try to use the results of that meta analysis to generate a forest plot based on that data I get the error message 'Error in catmapobject$ci : $ operator is invalid for atomic vectors' Am I right in thinking the order should be follows: catmapobject1<-catmap('rs2305764.txt', 0.95, TRUE, TRUE) catmap.forest(catmapobject1, TRUE, TRUE) I think I am failing to assign the results of the meta anlaysis - catmap('rs2305764.txt', 0.95, TRUE, TRUE)--- to an object in R, and then have catmap.forest act on that object. thanks Matthew [[alternative HTML version deleted]]