In GEE, several methods have been proposed for correcting for bias when the cluster size is small to moderate (<40). Some have proposed alternative variance estimators, e.g. Morel, Bokossa, and Neerchal (2003), while others have described methods for obtaining bias-corrected estimates of regression coefficients, e.g. Lunardon and Scharfstein (2017).
Would it be advisable to employ both these methods simultaneously?
Lunardon & Scharfstein (2017) https://onlinelibrary.wiley.com/doi/full/10.1002/sim.7366
Morel et al. (2003) https://onlinelibrary.wiley.com/doi/abs/10.1002/bimj.200390021