jaspIRT

A JASP module for Item Response Theory (IRT) and Rasch analysis of dichotomous items.

Features

• Models: Rasch, 1PL, 2PL, 3PL, 3PLu, 4PL, and 5PL (asymmetric logistic)
• Model comparison: Log-likelihood, AIC, BIC, SABIC, M², CFI, TLI
• Micro-level: Item frequencies, polarity, and direction
• Meso-level: Person measures, item difficulties, discrimination/guessing parameters, item fit (infit/outfit)
• Plots: Wright Maps, item fit plots, ICC/TIC curves, infit-outfit scatterplots
• DIF analysis: Mantel-Haenszel, standardization, logistic regression, SIBTEST, Breslow-Day, Lord, Raju, and IRT-based comparisons with DIF plots

Installation

1. Clone this repository
2. Open JASP and go to Preferences → Advanced
3. Set the development module path to this repository
4. Click the + button in the ribbon and install the development module

Reference

Tutorial: Development of a JASP module