[R] Survival analysis and comparing survival curves

Bert Gunter gunter.berton at gene.com
Thu Feb 23 19:10:53 CET 2012

DEAR R-girl:

On Thu, Feb 23, 2012 at 8:12 AM, R-girl <jhovinen at gmail.com> wrote:
> Hei,
> I have a one simple question which does not seem to be that simple as I
> cannot find any solution/answer:
> Is it possible to compare multiple survival curves in R with
> survdiff-function when there is interaction term involved in predictor
> variables (and this interaction is significant)?

I have one simple answer. Get local statistical help. You do not
understand the meaning of an interaction.

-- Bert

> Example:
> survdiff(Surv(death,status)~treatment*gapsize)
> R is making "problems" with it ie.e. it does not want to perform the test.
> And all the examples I have found so far, may involve multiple predictor
> variables but in additive format (e.g. treatment+gapsize).
> If survdiff is not the way to go, are there any other solutions in order to
> compare statistically the curves i.e. if they differ significantly from each
> other?
> I would really appreciate if someone can answer!
> Cheers, Minna
> --
> View this message in context: http://r.789695.n4.nabble.com/Survival-analysis-and-comparing-survival-curves-tp4414316p4414316.html
> Sent from the R help mailing list archive at Nabble.com.
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> and provide commented, minimal, self-contained, reproducible code.


Bert Gunter
Genentech Nonclinical Biostatistics

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