AUC {MKclass}

Compute AUC

Description

The function computes AUC.

Usage

AUC(x, y, group, switchAUC = TRUE, na.rm = TRUE)

Arguments

x

numeric vector.

y

numeric vector. If missing, group has to be specified.

group

grouping vector or factor.

switchAUC

logical value. Switch AUC; see Details section.

na.rm

logical value, remove NA before computation of AUC.

Details

The function computes the area under the receiver operating characteristic curve (AUC under ROC curve).

If AUC < 0.5, a warning is printed and 1-AUC is returned. This behaviour can be suppressed by using switchAUC = FALSE

The implementation uses the connection of AUC to the Wilcoxon rank sum test; see Hanley and McNeil (1982).

Value

AUC value.

Author(s)

Matthias Kohl [e-mail]

References

J. A. Hanley and B. J. McNeil (1982). The meaning and use of the area under a receiver operating characteristic (ROC) curve. Radiology, 143, 29-36.

Examples

set.seed(13)
x <- rnorm(100) ## assumed as log2-data
g <- sample(1:2, 100, replace = TRUE)
AUC(x, group = g)
## avoid switching AUC
AUC(x, group = g, switchAUC = FALSE)