[R] stepAIC + cox.zph

Hi, I'm using stepAIC with a CoxPH model on some data. As we expect, there are a bunch of predictors, and stepAIC throws some out and then converges on others. Anyway, when I run cox.zph on the final model, I get some evidence of Beta(t) time dependence. Should I be concerned about the impact of

[R] coxph diagnostics plot for shape of hazard function?

Hi, I've been banging my head against the following problem for a while and thought the fine people on r-help might be able to help. I'm using the survival package. I'm studying the survival rate of a population with a preexisting linear-like event rate (there are theoretical reasons to believe

[R] Coxph and loglik converged before variable X

Hi, I'm doing some coxph fits using the survival package. There are a large number of potential predictors and so I was considering using stepAIC for model selection. However, in the early stages I'm getting complaints like the following: Warning message: In fitter(X, Y, strats, offset, init,