Vikky, You'll notice that the model containing sex in addition to age has a higher apparent Dxy as you would expect [R^2 is not higher because it captures only the age effect]. The validated Dxy's may be as they are because of the very low number of bootstrap resamples (10) that you used.
Please following the posting guide, i.e., include a simple self-reproducing script that I can run - one that simulates its own dataset. Please switch to the rms package is this is the one that is being fully supported. See http://biostat.mc.vanderbilt.edu/Rrms. Frank ----- Frank Harrell Department of Biostatistics, Vanderbilt University -- View this message in context: http://r.789695.n4.nabble.com/Interpreting-the-example-given-by-Prof-Frank-Harrell-in-Design-validate-cph-tp3316820p3317265.html Sent from the R help mailing list archive at Nabble.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.
