Dear All, I was wondering why survreg (in survival package) can not handle three-way interactions. I have an AFT (accelerated failure time) model with a frailty term. If the model is restricted to two-way interactions, survreg and gamlss.cens (with random() term) give very similar results, except for the intercept (I do not know why it differs, anyway, if other coefficients are pretty the same). The aftreg function in the eha package could handle three-way interactions, but no frailty. Streg in Stata works fine with three-way interactions and frailty. However, 1) in the two-way interaction setting, Stata's results differ from those of gamlss and survreg, 2) I prefer R over Stata. So it seems that I can use gamlss.cens to analyze my data, but it would be more comfortable to use a dedicated library. Is there a theoretical reason that survreg does not provide the possibility of higher-order interactions, or is merely a programmatic issue?
Best, Denes ______________________________________________ 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.
