[R] obtainl survival curves for single strata

[Bond, Stephen]

Dear useRs,

What is the syntax to obtain survival curves for single strata on many subjects?

I have a model based on Surv(time,response) object, so there is a single row per subject and no start,stop and no switching of strata.

The newdata has many subjects and each subject has a strata and the survival based on the subject risk and the subject strata is needed.

If I do

newpred <- survfit(cph.approve,new=newapp,se=F)

I get all strata for every subject.

Attempting

> newpred <- survfit(cph.approve,new=newapp,id=CertId,se=F)
Error in survfit.coxph(cph.approve, new = newapp, id = CertId, se = F) : 
  The individual option is  only valid for start-stop data
> newpred <- survfit(cph.approve,new=newapp,indi=T,se=F)
Error in survfit.coxph(cph.approve, new = newapp, indi = T, se = F) : 
  The individual option is  only valid for start-stop data

Please, advise if obtaining a single strata for a basic (time,response) model is possible? Due to differing lengths of the surv for different strata this will not go in a "wide" data.frame without padding.

Thanks everybody and have a great day.

Stephen B