enmSdmX (version 1.2.12)

evalAUC: Weighted AUC

Description

This function calculates the area under the receiver-operator characteristic curve (AUC) following Mason & Graham (2002). Each case (presence/non-presence) can be assigned a weight, if desired.

Usage

evalAUC(
  pres,
  contrast,
  presWeight = rep(1, length(pres)),
  contrastWeight = rep(1, length(contrast)),
  na.rm = FALSE,
  ...
)

Value

A Numeric value.

Arguments

pres

Vector of predictions for "positive" cases (e.g., predictions at presence sites).

contrast

Vector of predictions for "negative" cases (e.g., predictions at absence/background sites).

presWeight

Weights of positive cases. The default is to assign each positive case a weight of 1.

contrastWeight

Weights of contrast cases. The default is to assign each case a weight of 1.

na.rm

Logical. If TRUE then remove any positive cases and associated weights and contrast predictions and associated weights with NAs.

...

Other arguments (unused).

References

Mason, S.J. and N.E. Graham. 2002. Areas beneath the relative operating characteristics (ROC) and relative operating levels (ROL) curves: Statistical significance and interpretation. Quarterly Journal of the Royal Meteorological Society 128:2145-2166. tools:::Rd_expr_doi("10.1256/003590002320603584")

See Also

pa_evaluate, evalMultiAUC

Examples

pres <- seq(0.5, 1, by=0.1)
contrast <- seq(0, 1, by=0.01)

# unweighted
evalAUC(pres, contrast)

# weighted (weight presences with low predictions more)
presWeight <- c(1, 1, 1, 0.5, 0.5, 0.5)
evalAUC(pres, contrast, presWeight=presWeight)

# weighted (weight presences with high predictions more)
presWeight <- c(0.5, 0.5, 0.5, 1, 1, 1)
evalAUC(pres, contrast, presWeight=presWeight)

# weight presences and absences
contrastWeight <- sqrt(contrast)
evalAUC(pres, contrast, presWeight=presWeight, contrastWeight=contrastWeight)