Hi, Newbie here, just joined the list. I discovered something interesting when performing a mixed between and within (repeated measure) ANOVA in R. The error terms (SS actually I guess) are inflated by the number of factors of the within measure. This just seems wrong. I think I'm doing it right e. g. subj grp test x 1 1 1 ... 1 1 1 1 1 2 1 1 2 2 2 1 2 2 1 2 2 2 2 2 2 So, the anova is done with aov (x~ grp*test + Error(subj/test)) Is there something I am doing wrong here? On a related note can I properly analyze a subset of between measures by adding something to my aov command instead of aggregating the data? thanks John