Re: [R] Difference between R and SAS in Corcordance index in ordinal logistic regression

2013-01-28 Thread Frank Harrell
For lrm fits, predict(fit, type='mean') predicts the mean Y, not a probability. Frank __ 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 prov

Re: [R] Difference between R and SAS in Corcordance index in ordinal logistic regression

2013-01-28 Thread Olivier Collignon
derbilt.edu > To: r-h...@stat.math.ethz.ch > Subject: Re: [R] Difference between R and SAS in Corcordance index in ordinal > logistic regression > > Please define 'mean probabilities'. > > To compute the C-index or Dxy you need anything that is monotonically > rela

Re: [R] Difference between R and SAS in Corcordance index in ordinal logistic regression

2013-01-24 Thread Frank Harrell
es are computed differently ? Thank for your help and best regards, OC Date: Thu, 24 Jan 2013 05:28:13 -0800 From: f.harrell@ To: r-help@ Subject: Re: [R] Difference between R and SAS in Corcordance index in ordinal logistic regression lrm does some binning to make the calculations fas

Re: [R] Difference between R and SAS in Corcordance index in ordinal logistic regression

2013-01-24 Thread Olivier Collignon
oject.org > Subject: Re: [R] Difference between R and SAS in Corcordance index in ordinal > logistic regression > > lrm does some binning to make the calculations faster. The exact calculation > is obtained by running > > f <- lrm(...) > rcorr.cens(predict(f), DA), w

Re: [R] Difference between R and SAS in Corcordance index in ordinal logistic regression

2013-01-24 Thread Frank Harrell
lrm does some binning to make the calculations faster. The exact calculation is obtained by running f <- lrm(...) rcorr.cens(predict(f), DA), which results in: C IndexDxy S.D. nmissing 0.96814404 0.93628809 0.0380833632.