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Get Distance Cutoffs

get-cutoffs.Rd

For given true class names and predictions, calculate the maximal perpendicular distance to the unit line, its corresponding specificity, then the cutoff corresponding to that specificity.

For a given specificity, calculate the corresponding cutoff (operating point) from a set of predictions.

Usage

get_max_cutoff(truth, predicted, pos_class)

get_spec_cutoff(truth, predicted, spec, pos_class)

Arguments

truth

character(n) or factor(n). A vector of true class names. In most instances you will have to also pass a pos_class argument defining the positive/event class.

predicted

numeric(n). A numeric vector of class probabilities.

pos_class

character(1). Name of the "positive" or "event" class.

spec

numeric(1). The desired specificity.

Value

get_max_cutoff(): a numeric cutoff representing the operating point at the maximal perpendicular distance from the unit line.

get_spec_cutoff(): a numeric cutoff representing the operating point for a given specificity.

See also

calc_roc_perpendicular(), roc_xy()

Author

Stu Field

Examples

n <- 20
withr::with_seed(122, {
  true <- sample(c("control", "disease"), n, replace = TRUE)
  pred <- runif(n)
})
get_max_cutoff(true, pred, "disease")
#> [1] 0.763952

# via specificity
get_spec_cutoff(true, pred, 0.4, "disease")
#> [1] 0.5366686