model.MIRT: Compute MIRT Item Response Probabilities

In ForceChoice: Forced-Choice Modeling Based on Item Response Theory and Cognitive Diagnostic Models

Compute MIRT Item Response Probabilities

Description

Computes the probability of a correct response for each person–item combination under the multidimensional 1PL–4PL models. This is the core IRF (item response function) used throughout the package.

Usage

model.MIRT(theta, par)

Arguments

theta	An N \times D matrix of latent trait values.
par	An I \times (D+3) parameter matrix with columns a1..aD, b, c, d, where b is the item difficulty. The linear predictor is \mathbf{a}_i'\boldsymbol{\theta}_j - b_i.

Value

An N \times I matrix of response probabilities P(Y_{ij} = 1 \mid \boldsymbol{\theta}_j).

See Also

fit.MIRT for the full model specification.

ForceChoice documentation built on Sept. 13, 2026, 1:06 a.m.