There are two z-scores reported in the summary: Naive z and Robust z. pvalue=2*min(pnorm(z-score), 1-pnorm(z-score)) # two-sided test -- View this message in context: http://r.789695.n4.nabble.com/gee-p-values-tp2533835p2534302.html Sent from the R help mailing list archive at Nabble.com.