I think it should be the negative of the first Dxy but this is all why the posting guide says to create the simplest self-defined example that shows the problem. That way I could run it and get to the bottom of this. See the help file for cph which has examples of simulating test data. Try to have only two covariates. 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-tp3316820p3319138.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.
