Question about cluster() and frailty() in coxph function

[duo wan <duo_wan@yahoo.com>]

Dear S-users,

 

I have one question about using cluster() and frailty() in coxph function. I have one data set with family id and medical center id. We first used cluster(familyid) to adjust for clustering within family ids. now we also try to adjust for center effects as a random effects using frailty(). Is it possible to specify these two functions cluster() and frailty() in one coxph() model?

 

thanks,

 

Vincent

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