[R] Coxph with factors

Kylie-Anne Richards kar at itga.com.au
Thu Jul 14 08:46:29 CEST 2005


I am fitting a coxph model with factors. I am running into problems when
using 'survfit'. I am unsure how R is treating the factors when I fit, say:
>        DATA<-data.frame(time.sec,done,f.pom=factor(f.pom),po,vo)
>        final<-coxph(Surv(time.sec,done)~f.pom*vo+po,data=DATA)
>         final.surv<-survfit((final), individual=T,conf.type="log-log")
>         print(final.surv)

Also, when I trying using survfit with presepecified values for the
covariates and factor (i.e. '0' to get the baseline) I get an error message,
which I think is a result of my inability to specify the factors in the
correct manner.

I would very much appreciate if somebody can help me out.

Thanks very much,


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