Tyler, The rcorr.cens, rcorrp.cens, and somers2 functions compute Dxy. That is a typo in the overview, which we'll fix. Dxy is the appropriate measure for binary Y, I think. It is a simple translation of the ROC area and does not penalize for ties on Y. Frank
Tyler Rinker wrote: > > Hello R Community, > > I'm continuing to work through logistic regression (thanks for all the > help on score test) and have come up against a new opposition. > > I'm trying to compute Somers Dyx as some suggest this is the preferred > method to Somers Dxy (Demaris, 1992). I have searchered the [R] archieves > to no avail for a function or code to compute Dyx (not Dxy). The overview > of Hmisc has mention of Dyx for the rcorr.cens function but this appears > to be a misprint because the manual states the function finds Dxy. Peng > and So (1998) state that the Dyx is easily calculated in SAS (which tells > me the same is possible for [R]). > > Yang, K., Miller, G. J., & Miller, G. state that: > > (Tau-b)^2=Somers Dxy * Somers Dyx > > so maybe an approach would be to write a function that is: > > Somers Dyx<-(Tau-b)^2/Somers Dxy > > I just don't want to waste time if this is incorrect logic and/or there's > an easier way to calculate this thing; perhaps theres a golden function > already created in an [R] package that I'm overlooking. > > Thanks in advance, > Tyler > [[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. > ----- Frank Harrell Department of Biostatistics, Vanderbilt University -- View this message in context: http://r.789695.n4.nabble.com/Somers-Dyx-tp3593119p3593649.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.
