[R] anova.coxph with subsets of data
Therneau, Terry M., Ph.D.
therneau at mayo.edu
Wed Jan 29 15:35:24 CET 2014
--- begin included message ---
But If I do
> fit <- coxph(Surv(futime, fustat) ~ resid.ds *rx + ecog.ps, data = ovarian, subset=ovarian$age>50)
> anova(fit)
> fit2 <- coxph(Surv(futime, fustat) ~ resid.ds +rx + ecog.ps, data=ovarian, subset=ovarian$age>50)
> anova(fit2,fit)
The first p-value seems to be wrong.
Would anybody please explain to me why?
Cheers,
Oscar
---- end inclusion ----
The p-value seems wrong because it is wrong. You've found a bug in the survival package.
(It has to do with missing values, and the attempt of anova.coxph to ensure that it does
not fit a sequence of models such that an observation is dropped partway through the list.)
Terry Therneau
More information about the R-help
mailing list