[R] kidney survival data

Thomas Lumley tlumley at u.washington.edu
Mon Oct 1 18:02:57 CEST 2001

On Thu, 27 Sep 2001, Teresa Cristina Martins Dias wrote:

> Dear all, in survival5, kidney data set, appears in help page:
> "survival5 does not reproduce the original analysis."
> What   does it means?

The dataset has several ties in the failure times, so handling of ties
matters.  According to Therneau the original paper didn't handle the ties
quite correctly.  The effect would usually be invisibly small, but the
REML-like computations seem to be more sensitive to ties than the usual
Cox model.  The difference from the original paper is quite small, but the
comment is there as a reassurance that it is a known difference.


Thomas Lumley			Asst. Professor, Biostatistics
tlumley at u.washington.edu	University of Washington, Seattle

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