youden {cenROC}

Computes optimal cutoff point using the Youden index criteria

Description

This function computes the optimal cutoff point using the Youden index criteria of both right and interval censored time-to-event data. The Youden index estimator can be either empirical (non-smoothed) or smoothed with/without boundary correction.

Usage

youden(est, plot = "FALSE")

Arguments

est

The object returned either by cenROC or IntROC.

plot

The logical parameter to see the ROC curve plot along with the Youden inex. The default is TRUE.

Details

In medical decision-making, obtaining the optimal cutoff value is crucial to identify subject at high risk of experiencing the event of interest. Therefore, it is necessary to select a marker value that classifies subjects into healthy and diseased groups. To this end, in the literature, several methods for selecting optimal cutoff point have been proposed. In this package, we only included the Youden index criteria.

Value

Returns the following items:

Youden.index The maximum Youden index value.

cutopt The optimal cutoff value.

sens The sensitivity corresponding to the optimal cutoff value.

spec The specificity corresponding to the optimal cutoff value.

References

Beyene, K. M. and El Ghouch A. (2022). Time-dependent ROC curve estimation for interval-censored data. Biometrical Journal, 64, 1056– 1074.

Youden, W.J. (1950). Index for rating diagnostic tests. Cancer 3, 32–35.

Examples

library(cenROC)

# Right censored data
data(mayo)

resu <- cenROC(Y=mayo$time, M=mayo$mayoscore5, censor=mayo$censor, t=365*6, plot="FALSE")
youden(resu,  plot="TRUE")

# Interval censored data
data(hds)

resu1 = IntROC(L=hds$L, R=hds$R, M=hds$M, t=2)
youden(resu1,  plot="TRUE")