On Nov 1, 2013, at 11:16 AM, cesar garcia perez de leon wrote: > Dear all, > > We are conducting a study in with a set of covariates and a time to event > outcome. > Covariates b1 and b3 violate proportionality.
Can you describe the basis for that statement? > We applied a coxph with a „tt‰ term to evaluate the nature of time > dependence. > > Call: > coxph(formula = Surv(start - 1, stop, outcome) ~ tt(b1) + > b5 + tt(b3) + b4, data = data, tt = function(x, t, ...) pspline(x + > t/90)) > > We would like to plot the predicted effects. Following the logic of the tt > function, does it make sense to plot the residuals against the results from > the model with tt for the upsetting covariates? > > As far as we know the there has not been updates of survfit for the tt > function. So, we are unsure as to how to plot our curves. > > I would appreciate if someone can give me an advise or a publication > reference that can help us in this matter. Is there a reason not to use `cox.zph` and it's `print` and `plot` methods for this purpose? I think it is already offering what you are trying to re0invent. -- David Winsemius Alameda, CA, USA ______________________________________________ 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.
