caret (version 2.27)

roc: Compute the points for an ROC curve

Description

Computes sensitivity and specificity for a variety of cutoffs

Usage

roc(data, class, dataGrid = TRUE, gridLength = 100, positive = levels(class)[1])

Arguments

data

a numeric variable to cut along

class

a factor with class memberships. There must be only two classes.

dataGrid

should the data define the grid of cut-points? If not a sequence of evenly spaced intervals is used.

gridLength

number of intervals to use if the data do not define the grid.

positive

a character string for the level of the class variable that defines a "positive" event

Value

• A matrix of results with columns "cutoff", "sensitivity" and "specificity"

See Also

sensitivity, specificity, aucRoc

Examples

set.seed(6)
testData <- data.frame(
   x = c(rnorm(200), rnorm(200) + 1),
   group = factor(rep(letters[1:2], each = 200)))
   
densityplot(~testData$x, groups = testData$group, auto.key = TRUE)   
   
roc(testData$x, testData$group)