# R: Test for Proportional Odds in the Proportional-Odds...

poTest {car} | R Documentation

## Test for Proportional Odds in the Proportional-Odds Logistic-Regression Model

### Description

The `poTest` function implements tests proposed by Brant (1990) for proportional odds for logistic models fit by the `polr` function in the MASS package.

### Usage

    poTest(model, ...)
    ## S3 method for class 'polr'
    poTest(model, ...)
    ## S3 method for class 'poTest'
    print(x, digits=3, ...)

### Arguments

`model` | a proptional-odds logit model fit by `polr`.
`x` | an object produced by `poTest`.
`digits` | number of significant digits to print.
`...` | ignored.

### Value

`poTest` returns an object meant to be printed showing the results of the tests.

### Author(s)

John Fox jfox@mcmaster.ca

### References

R. Brant, "Assessing proportionality in the proportional odds model for ordinal logistic regression." Biometrics 46: 1171–1178, 1990.

### Examples

    if (require("MASS")){
        .W <- Womenlf
        .W$partic <- factor(.W$partic, levels=c("not.work", "parttime", "fulltime"))
        poTest(polr(partic ~ hincome + children + region, data=.W))
    }

[Package car version 3.0-2 Index]