Dear David, Thank you for your reply. I have come across rcorrp.cens before. However, I'm not sure it does quite what I want it to. It seems to compare whether one predictor is more concordant than another within the same survival function. I want to see whether one predictor is more concordant than another over two survival functions hence I fitted two rcorrcens functions.
E.g. if I have a development data set with a variable for age and a validation data set for age then I want to know if the concordance is the same over the development and validation data sets. Thank you, Laura On 5 May 2011 16:09, David Winsemius <dwinsem...@comcast.net> wrote: > > On May 5, 2011, at 8:20 AM, Laura Bonnett wrote: > > Dear All, >> >> I am trying to calculate a 95% confidence interval for the difference in >> two >> c statistics (or equivalently D statistics). In Stata I gather that this >> can be done using the lincom command. Is there anything similar in R? >> > > Have you looked at rcorrp.cens {Hmisc}? > > <snipped> > >> >> [[alternative HTML version deleted]] >> > > > Please post in plain text. > > -- > David Winsemius, MD > West Hartford, CT > > [[alternative HTML version deleted]] ______________________________________________ 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.