dichotomous.to.pcm: Convert Rasch difficulties of many dichotomous items to...

In CambridgeAssessmentResearch/unimirt: Applications of Unidimensional IRT using the R Package 'mirt'

Convert Rasch difficulties of many dichotomous items to Partial Credit Model (PCM) thresholds

Description

Given a set of Rasch difficulties from n dichomtomous items, calculate the equivalent thresholds for a single polytomous item (with n+1 categories) that fits the partial credit model (PCM).

Usage

dichotomous.to.pcm(dich_diffs)

Arguments

dich_diffs

A vector of Rasch difficulties. The length of the vector represents the number of dichotomous items considered.

Value

A vector of thresholds for the partial credit model (PCM).

Examples

## Not run: 
dichotomous.to.pcm(c(0,0))
pcm.to.dichotomous(c(-0.6931472,0.6931472))

dichotomous.to.pcm(c(-2,-4,1))
pcm.to.dichotomous(c(-4.132845,-1.922140,1.054985))

dichotomous.to.pcm(c(-1,-1,1,1))
pcm.to.dichotomous(c(-1.8200752,-0.6243906,0.6243906,1.8200752))

## End(Not run)

CambridgeAssessmentResearch/unimirt documentation built on June 10, 2025, 6:03 a.m.