R^2 for GEE using the formula of Ballinger (2004)

[Thorgal]

Hi everyone,

I tried to calculate a R^2 (R-squared) for a GEE using the formula of Ballinger, G. A. (2004). Using Generalized Estimating Equations for longitudinal data analysis. Organizational Research Methods, 7, 127-159.

I could calculate the the R^2*m (correctly I hope), using ,among others the save-command "Predicted value of mean of response", but I don't know what the "m" stands for...? Anyone knows?