spatialEco (version 1.0-0)

concordance: Concordance test for binomial models

Description

Performs a concordance/disconcordance (C-statistic) test on binomial models.

Usage

concordance(y, p)

Arguments

y

vector of binomial response variable used in model

p

estimated probabilities from fit binomial model

Value

A list class object with the following components:

concordance percent of positives that are greater than probabilities of nulls

is concordance inverse of concordance representing null class

tied number of tied probabilities

pairs number of pairs compared

References

Austin, P.C. & E.W. Steyerberg (2012) Interpreting the concordance statistic of a logistic regression model: relation to the variance and odds ratio of a continuous explanatory variable. BMC Medical Research Methodology, 12:82 Harrell, F.E. (2001) Regression modelling strategies. Springer, New York, NY. Royston, P. & D.G. Altman (2010) Visualizing and assessing discrimination in the logistic regression model. Statistics in Medicine 29(24):2508-2520

Examples

# NOT RUN {
data(mtcars)
dat <- subset(mtcars, select=c(mpg, am, vs))
glm.reg <- glm(vs ~ mpg, data = dat, family = binomial)
concordance(dat$vs, predict(glm.reg, type = "response")) 

# }