SMABS 2004 Jena University
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European Association of Methodology

Department of methodology and evaluation research

Jena University

Contributions: Abstract

Item Response Theory - a software review

Carsten Schmidt Thomas Kohlmann
Universit├Ąt Greifswald

Modern IRT-software applies a variety of IRT-models ranging from the 1-, 2-, or 3-parameter logistic model, multi-faceted and polytomous extensions of the Rasch model to multidimensional latent trait models and free mixtures of Rasch models and latent class models. This review focuses on the features of 8 stand-alone IRT-programs (ConQuest; LPCM-WIN; Multilog; Multira; Parscale; Rumm, Winmira, Winsteps). Additionally, the review briefly refers to a selection of other IRT-programs (Bilog; Logimo, MSP, Parella, Rascal, RSP, Rummfold, T-Rasch, XCalibre) and standard software packages.

An overview is given of the models that can be calculated, methods for estimating item and person parameters, the evaluation of model-fit and other program features such as the analysis of item parameter drift and differential item functioning. Technical aspects of the programs such as the user interface, graphical output, support of different file formats, required operating system, availability of demo-versions and costs will be compared.

The review shows a wide variety of program features in all the aspects mentioned. While some programs may only handle the 1 to 3-parameter logistic model, others offer a versatile calculation of complex models. Marginal maximum likelihood and conditional maximum likelihood estimates of item parameters are used most frequently. Documentation styles vary from application-oriented manuals to detailed explications of the implemented algorithms. Most programs run in a Windows environment and offer a graphical user interface. Some powerful programs are distributed as freeware while most are commercial with prices varying between approx. 150 and 700 Euro. The programs available are suitable to cover the needs of users with very different demands.