spatialEco (version 0.1-5)

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 nullsisconcordance inverse of concordance representing null classtied number of tied probabilitiespairs 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

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"))