2 messages · Osman Al-Radi, Frank E Harrell Jr
Dear R-help, Would it be appropriate to do the following to calculate a p-value for the difference between c-ind of x1 and c-inx of x2 using the output from rcorrp.senc()
r<-rcorrp.senc(x1,x1,y)
pValue<-1-pnorm((r[11]-r[12])/(r[2]/r[5])*1.96)
Osman O. Al-Radi, MD, MSc, FRCSC Chief Resident, Cardiac Surgery University of Toronto, Canada
Dear R-help, Would it be appropriate to do the following to calculate a p-value for the difference between c-ind of x1 and c-inx of x2 using the output from rcorrp.senc()
r<-rcorrp.senc(x1,x1,y)
pValue<-1-pnorm((r[11]-r[12])/(r[2]/r[5])*1.96)
Osman O. Al-Radi, MD, MSc, FRCSC Chief Resident, Cardiac Surgery University of Toronto, Canada
Osman, Because tests for differences in two ROC areas are not very powerful, rcorrp.cens changes the hypothesis to "are predictions from one method more concordant with the outcome than predictions from the other method, within paired predictions". You can't get a difference in ROC areas from the U-statistic computed by rcorrp.cens. Frank
Frank E Harrell Jr Professor and Chair School of Medicine
Department of Biostatistics Vanderbilt University