PPV {measures}

Positive predictive value

Description

Defined as: tp / (tp + fp). Also called precision. If the denominator is 0, PPV is set to be either 1 or 0 depending on whether the highest probability prediction is positive (1) or negative (0).

Usage

PPV(truth, response, positive, probabilities = NULL)

Arguments

truth

vector of true values

response

vector of predicted values

positive

positive class

probabilities

[numeric] vector of predicted probabilities

Examples

n = 20
set.seed(125)
truth = as.factor(sample(c(1,0), n, replace = TRUE))
probabilities = runif(n)
response = as.factor(as.numeric(probabilities > 0.5))
positive = 1
PPV(truth, response, positive, probabilities = NULL)