Just wanted to alert everyone regarding a problem that I only experience with R2.9.0 and not with R2.8.1 when I run both using exactly the same script and the same data. Here is what I do with my data "MyData", 2 predictors (V1 and V2) and my survival DV "Depvar":
library(survival) model<-coxph(Depvar~V1:V2+strata(ID),data=MyData,na.action=na.omit,method="breslow") When I look at summary(model), the very end of it looks like this in R2.8.1: Rsquare= 0.067 (max possible= 0.792 ) Likelihood ratio test= 169 on 24 df, p=0 Wald test = 144 on 24 df, p=0 Score (logrank) test = 164 on 24 df, p=0 When I look at summary(model), the very end of it looks like this in R2.9.0 (looks the same to me): Rsquare= 0.067 (max possible= 0.792 ) Likelihood ratio test= 168.8 on 24 df, p=0 Wald test = 144.1 on 24 df, p=0 Score (logrank) test = 164.0 on 24 df, p=0 Then, I run this line: utilities<-predict(model,newdata=expand.grid(V1=factor(1:5),V2=factor(1:5))) This line runs fine in R2.8.1 and gives me a vector of utilities. But when I run it in R2.9.0, I get: Error in model.frame.default(Terms2, newdata, xlev = object$xlevels) : variable lengths differ (found for 'V1') In addition: Warning message: 'newdata' had 25 rows but variable(s) found have 2415 rows I prefer not to get into the debugging of that whole thing. But thought that someone knowledgeable might get an idea about what might be wrong in the latest R version. -- Dimitri Liakhovitski MarketTools, Inc. dimitri.liakhovit...@markettools.com ______________________________________________ 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.
