I can't reproduce the problem.
Tell us what version of R and what version of the survival package.
Create a reproducable example. I don't know if some variables are numeric and some are
factors, how/where the "surv" object was defined, etc.
Terry Therneau
On 11/17/2012 05:00 AM, r-help-requ...@r-project.org wrote:
This works ok:
> cox = coxph(surv ~ bucket*(today + accor + both) + activity, data = data)
> fit = survfit(cox, newdata=data[1:100,])
but using strata leads to problems:
> cox.s = coxph(surv ~ bucket*(today + accor + both) + strata(activity),
> data = data)
> fit.s = survfit(cox.s, newdata=data[1:100,])
Error in model.frame.default(data = data[1:100, ], formula = ~bucket + :
number of variables != number of variable names
Note that the following give rise to the same error:
> fit.s = survfit(cox.s, newdata=data)
Error in model.frame.default(data = data, formula = ~bucket + today + :
number of variables != number of variable names
but if I use data implicitly, all is working fine:
> fit.s = survfit(cox.s)
Any idea on how I could solve this?
Best, and thank you,
ge
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