Modular Open-Source Software for Item Factor Analysis

• Published in: Educational and psychological measurement Vol. 75; no. 3; pp. 458 - 474
• Main Authors: Pritikin, Joshua N., Hunter, Micheal D., Boker, Steven M.
• Format: Journal Article
• Language: English
• Published: Los Angeles, CA SAGE Publications 01.06.2015; SAGE PUBLICATIONS, INC
• Subjects: Computer programming; Discriminant analysis; Factor Analysis; Open source software; Open Source Technology; Optimization algorithms; Parameter optimization; Software packages; Structural Equation Models; open-source; modular; item response theory; item factor analysis; Item Factor Analysis; Item Response Theory
• ISSN: 0013-1644; 1552-3888
• DOI: 10.1177/0013164414554615

This article introduces an item factor analysis (IFA) module for OpenMx, a free, open-source, and modular statistical modeling package that runs within the R programming environment on GNU/Linux, Mac OS X, and Microsoft Windows. The IFA module offers a novel model specification language that is well suited to programmatic generation and manipulation of models. Modular organization of the source code facilitates the easy addition of item models, item parameter estimation algorithms, optimizers, test scoring algorithms, and fit diagnostics all within an integrated framework. Three short example scripts are presented for fitting item parameters, latent distribution parameters, and a multiple group model. The availability of both IFA and structural equation modeling in the same software is a step toward the unification of these two methodologies.