Hello,
I have a multi-level, cohort dataset with three levels: repeat measures of a response (level 1), that are collected from individual participants (level 2) who are students within a school (level 3). I would like to do a generalized estimating equation (GEE) analysis of this clustered data, but to do so I need to specify ?nested? correlation structures (e.g. exchangeable, compound symmetric, Toeplitz) to account for the within-individual and within-cluster correlations.
Here is a reference paper that describes a nested exchangeable correlation structure and nested compound symmetry: doi:10.1111/j.1541-0420.2009.01374.x.
The geepack is available in R to do GEE analyses, but it seems to me that it only allows the user to specify a correlation structure via the geepack(??corstr = ?) option which only accounts for the within-individual correlations (that arise from repeated measures). Would it be possible to specify the nested correlation structures that I refer to here to also account for the within-cluster correlations using this package?
Thank you,
Edward