On May 6, 2011, at 6:22 PM, Eva Bouguen wrote:
Dear users,
In a study with recurrent events:
My objective is to get estimates of survival (obtained through a Cox
model) by rank of recurrence and by treatment group.
With the following code (corresponding to a model with a global
effect of the treatment=rx), I get no error and manage to obtain
what I want :
data<-(bladder)
model1<-coxph(Surv(stop,event)~rx+strata(enum)
+cluster(id),data=bladder)
data1<-data.frame(rx=1)
survfit(model1,newdata=data1)
But with the model with strata by treatment interaction
(corresponding to a model with an effect of the treatment by rank),
I get the following error:
model2<-coxph(Surv(stop,event)~rx*strata(enum)
+cluster(id),data=bladder)
data1<-data.frame(rx=1)
survfit(model2,newdata=data1)
Erreur dans strata(enum) : objet "enum" non trouvé =>error in
strata(enum) : object "enum" not found
Right. Looks like a perfectly clear error message to me .... you
created a newdata dataframe that did not have all the necessary
columns that you used on the RHS of your formula.
--
David Winsemius, MD
West Hartford, CT
______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
