[R] p-value of Logrank-Test

Thomas Lumley tlumley at u.washington.edu
Tue Jan 3 22:46:31 CET 2006

On Tue, 3 Jan 2006, Verena Hoffmann wrote:

> Hello!
> I want to compare two Kaplan-Meier-Curves by using the Logrank-Test:
> logrank(Surv(time[b], status[b]) ~ group[b])
> This way I only get the value of the test-statistic, but not the p-value.
> Does anybody know how I can get the p-value?

You don't say where you found the logrank() function, but

a)  The survdiff() function in the survival package gives p-values as well 
as test statistic for the logrank test

b) The test statistic presumably has a  chisquare null distribution, so 
pchisq() would turn it into a p-value.


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