Hi, I have a dataset (see attached) with 2 variables "Y" is binary,
"x" is a
continuous variable. I want to calculate area under the curve (AUC) for the ROC
curve, but I got different AUC values using ROC() from Epi package vs.
rcorr.cens() from rms package:
test<-read.table("test.txt",sep='\t',header=T,row.names=NULL)
y<-test$y
x<-test$x
library(Epi)
ROC(form=y~x,plot="ROC")
library(rms)
rcorr.cens(x,y)
lrm(y~x)
As you can see, ROC() gave an AUC 0.782, while both rcorr.cens() and lrm()
(C-index) gave AUC 0.813. That's a big difference. And I believe rms package
gave me correct answer. But anyone have any clue about the difference?
Thanks
John
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