Although someone on this list may respond, AFAICS this does not seem to be an R question for R-help.I would suggest that you spend some time with a local statistician.
A general observation: Statistical model assumptions neither :hold" nor "don't hold." Quoting George Box, "All models are wrong, but some are useful." Determining whether a coxph regression model is useful for your data and problem is something that I think only you and someone with statistical experience and insight into these models can decide. I do not understand how this can be done remotely. Cheers, Bert On Sat, Aug 10, 2013 at 9:14 PM, Soumitro Dey <soumitrod...@gmail.com> wrote: > Hello all, > > This may be a naive question but since I'm new to R/survival models, I > cannot figure it out the problem myself. > > I have a coxph model for my data and I am trying to test if the > proportional hazards assumption holds. Using cox.zph on the model I get a > global score: > > GLOBAL NA 4.20e+02 0.00e+00 > > Does this mean that the proportional hazard assumption does not hold? > When I plot the Schoenfeld residuals, generally the plots are across > the horizontal line which makes me think that the proportional hazards > assumption still holds. Could someone please clarify on this? > > A somewhat unrelated question: I have come across several papers which > just calculate the coxph model without the diagnostics for > proportional hazards assumption and interpret the results of the > regression directly. Should that be acceptable? Are there other ways > to show the goodness of the model? > > Thanks! > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. -- Bert Gunter Genentech Nonclinical Biostatistics Internal Contact Info: Phone: 467-7374 Website: http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
