Re: [R] fitting a gamma frailty model (coxph)

I looked at your data: > table(x, cluster) 1 2 3 4 5 6 0 0 48 0 48 48 0 1 48 0 48 0 0 48 Your covariate "x" is perfectly predicted by the cluster variable. If you fit a fixed effects model: coxph(Surv(time, event) ~ factor(cluster) +x) then the "x" variable is declared redu

[R] fitting a gamma frailty model (coxph)

Dear all, I have a data setwith 6 clusters, each containing 48 (possibly censored, in which case "event = 0") survival times. The "x" column contains a binary explanatory variable. I try to describe that data with