IRTm
Introduction
Description
Item response theory (IRT) models are the central tools in modern measurement and advanced psychometrics. IRTm is a MATLAB IRT modeling toolbox that can fit a large variety of IRT models for binary responses. A design-matrix approach is followed, giving the end-user control and flexibility in building a model that goes beyond standard models like the Rasch or 2PL model. For instance, the very recent copula IRT models to handle local item dependencies are included, as well as the possibility to take into account differential item functioning, and many more. Data simulation is supported.
Authors
IRTm was created by Johan Braeken and Francis Tuerlinckx of the Research Group of Quantitative Psychology and Individual Differences of the Katholieke Universiteit Leuven.
References
- De Boeck, P., & Wilson, M. (Eds.). (2004). Explanatory item response models: A generalized linear and nonlinear approach. New York: Springer.
- Braeken, J., & Tuerlinckx, F. (2009). Investigating latent constructs with item response models: A MATLAB IRTm toolbox. Behavior Research Methods, 41, 1127-1137. doi:10.3758/BRM.41.4.1127
Getting IRTm
What
The download package is a zip-file that you may unpack in any folder of choice. After unpacking, you should start MATLAB and change its current directory to the folder in which you have unpacked the files in question. Type IRTmInstall after the command prompt to complete the toolbox' installation. Helpfiles, an introductory document, and an example (IRTmCase.m, also accessible as demo) are included.
Conditions
IRTm is offered free of charge to anyone interested in Item response theory models, provided that it is not used for financial profit and that you properly cite the software and the papers mentioned above. Requests to use IRTm for any commercial purpose must be directed to the authors. IRTm comes without any warranty of any kind. You are not allowed to redistribute a downloaded copy of IRTm to others. If you want others to use IRTm, refer them to this website. See here for full license information.
How
To get the software, you have to fill out your name and e-mail address in a form. After submitting that information, an e-mail containing the address where you can download the software once will be sent to you. Click here to proceed to the download area.