How do I specify a partially completed survival analysis model?
On Nov 23, 2009, at 12:50 PM, David Winsemius wrote:
On Nov 20, 2009, at 1:27 PM, David Winsemius wrote:
On Nov 20, 2009, at 11:07 AM, RWilliam wrote:
In reply to suggestion by David W., setting an offset parameter doesn't seem to work as R is not recognizing the "X2" part of coxph( Surv(Time,Censor)~X1, offset=log(4.3*X2), data= a ). Also, here's some sample data:
The problem, arising as a result of not having a dataset against which to test my memories of syntactic niceties, is that glm and coxph use different methods of supplying offsets.
It's been pointed out to me that coxph()'s required syntactic incorporation of offsets is the same as glm()'s preferred inclusion in the formula, and that my erroneous impression that a separate offset argument is necessary might have be the result of "SAS poisoning". I suspect that "infection" is the more correct biomedical analogy, since I copied my use from another who was probably the index case. That usage was also similar to the separate specification of offsets (e.g. $CAL LPY=%LOG(PY) $OFFSET LPY) in GLIM which was my statistical upbringing.
Would that be SAS1N1 and is there a vaccine that one can distribute to universities and corporations to prevent the spread of the infection? ;-) Regards, Marc Schwartz