polychoric: Polychoric Correlation

In exametrika: Test Theory Analysis and Biclustering

Polychoric Correlation

Description

Calculate the polychoric correlation coefficient between two polytomous (categorical ordinal) variables. Polychoric correlation estimates the correlation between two theorized normally distributed continuous latent variables from two observed ordinal variables.

Usage

polychoric(x, y)

Arguments

x	A polytomous vector (categorical ordinal variable)
y	A polytomous vector (categorical ordinal variable)

Details

This function handles missing values (coded as -1 or NA) using pairwise deletion. The estimation uses maximum likelihood approach with Brent's method for optimization.

Value

The polychoric correlation coefficient between x and y

Examples

# Example with simulated data
set.seed(123)
x <- sample(1:5, 100, replace = TRUE)
y <- sample(1:4, 100, replace = TRUE)
polychoric(x, y)

exametrika documentation built on Aug. 21, 2025, 5:27 p.m.