[R] Error in using coxph()

[Prof Brian Ripley]

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