Item Characteristic Curve Simulator

Difficulty parameter (b)

Discrimination parameter (a)

Pseudo-guessing parameter (c)

upper asymptote (d)

Respondent's latent trait (theta)

This simple tool was developed to help teaching about Item Response Theory (IRT). It simulates the item characteristic curve (ICC) under four-parameters (4PL) binary IRT model.

© 2017 Hynek Cígler
Department of psychology, Faculty of Social Studies
Masaryk University, Brno, Czech Republic
Source code on GitHub

Respondent's probability of correct response is .

The item response function of the 4PL model is: