SUBIRANA CACHINERO, ISAAC wrote: > Hi everyone, > > I am doing 5 years mortality predictive index score with survival analysis > using a Cox proportional hazard model where I have a continous predictive > variable and a right censored response which is the mortality, and the > individuals were followed a maximum of 7 years. > > I'd like to asses the discrimination ability of survival analysis Cox model > by computing a ROC curve and area under the curve for a fixed time (5 years), > taking into account that the response is not binary but right censored. > > So, is there a function that computes a ROC curve under right censored > survival data? > > Thank you in advance.
I don't find ROC curves themselves very useful but the area under them is useful and is a simple translation of the Somers' Dxy rank correlation between predicted survival probability (or anything monotonically related to it just is log hazard) and observed survival time. Dxy = 2*(C-.5) where C is the concordance index, a generalization of ROC area not requiring choosing a specific time point. You can get this in the rcorr.cens function in the Hmisc package. Frank > > > > > > Isaac Subirana: [EMAIL PROTECTED] > > Institut Municipal d'Investigació Mèdica (IMIM), > > Barcelona (Spain) > > > > > [[alternative HTML version deleted]] > > > > ------------------------------------------------------------------------ > > ______________________________________________ > R-help@stat.math.ethz.ch mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html -- Frank E Harrell Jr Professor and Chair School of Medicine Department of Biostatistics Vanderbilt University ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
