[R] R survAUC Package

[kevinod]

I have a concern about the survAUC package option AUC.cd.  

I am exploring package functionality, specifically AUC statistics for Cox
Regression, for a small academic project

When utilizing this package on the ovarian data set within that package I
obtain an AUC statistic of 0.3322928.  When AUC calculations use a
dichotomous outcome such as this, see included R code, the result should lie
between 0.5 and 1, not 0.33.

Please explain this, I am not certain that the algorithm that is being
utilized for this package is correct.

Thank you

Kevin O’Donnell, MS Work Environment, MS Env Eng.,  MS Const Project Mgmt
Graduate Student
Department of Biostatistics
Boston University School of Public Health
715 Albany Street Boston, MA

617-480-1677

x11(h=8,w=11)
fit = survfit(Surv(futime,fustat) ~ rx)
plot(fit, mark.time=FALSE, xscale=365.25,main="Plot of Survival Curves by
Prescription Status",
        xlab='Length of Survival', ylab='Proportion of Individuals who have
Survived')
lines(fit[1], lwd=3,lty=2:3, xscale=365.24,col=2)
lines(fit[2], lwd=2,lty=2:2, xscale=365.24,col=3)
legend(.2,.2, c("No treatment", "treatment"), lwd=3,lty = 2:3) 


TR2 = ovarian[1:16,]
TE2 = ovarian[17:26,]
train.fit2  = coxph(Surv(futime, fustat) ~ rx,
                    x=TRUE, y=TRUE, method="efron", data=TR)
lp2 = predict(train.fit) 
lpnew2 = predict(train.fit2, newdata=TE2)
Surv.rsp2 = Surv(TR2$futime, TR2$fustat)
Surv.rsp.new2 = Surv(TE2$futime, TE2$fustat)
times2 = seq(10, 1000, 10)                  
 
AUC_CD2 = AUC.cd(Surv.rsp2, Surv.rsp.new2, lp2, lpnew2, times2)


AUC_hc2 = AUC.hc(Surv.rsp2, Surv.rsp.new2, lpnew2, times2)


AUC_sh2 = AUC.sh(Surv.rsp2, Surv.rsp.new2, lp2, lpnew2, times2)


AUC_Uno2 = AUC.uno(Surv.rsp2, Surv.rsp.new2, lpnew2, times2)




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