[R] Error in using coxph()
Prof Brian Ripley
ripley at stats.ox.ac.uk
Sun May 16 18:24:32 CEST 2004
On 16 May 2004, Peter Dalgaard wrote:
> Prof Brian Ripley <ripley at stats.ox.ac.uk> writes:
>
> > Note you said you used 1-F but the output said you used F. You also say
> > `1-F is a vector of '0's' so I think you may have declared that all
> > observations are right-censored. (NB if you give Surv an event vector of
> > all 1's it is ambiguous, so don't do this.)
>
> Actually, it *is* documented that this is interpreted as "all-died"
Yes, I know. What I do not know is what the OP actually did, since the
case of 1-F == 0 and using F should mean no censoring, and you cna omit
the event arg in that case.
Nevertheless, it *is* ambiguous (has two possible meanings) and you have
to check the documentation to know which is used (unless you have an
incredibly good memory or make a habit of doing this).
> and the advice in ?Surv is just to avoid 1/2 coding if all data are
> censored. It's a bit puzzling that we don't allow explicit
> disambiguation (e.g., by passing the event as a two-level factor),
> though.
Logical is allowed and clearer.
--
Brian D. Ripley, ripley at stats.ox.ac.uk
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
Oxford OX1 3TG, UK Fax: +44 1865 272595
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