flexMIRT

flexMIRT is statistical software, authored by Li Cai and commercially distributed by Vector Psychometric Group, LLC, for item analysis and test scoring. Item analysis includes the estimation of item response theory (IRT) models and diagnostic classification models, both of which are widely used in educational research and measurement. The development of ever-more complex modeling frameworks and IRT models requires an adaptable and regularly updated software program capable of keeping pace with advancements in both computing and statistical/educational measurement theory; flexMIRT seeks to fulfill this need. This entry provides a broad [Page 683]overview of the capabilities of flexMIRT and briefly details licensing information.

First released in 2012, flexMIRT was initially published as a statistical software primarily for multidimensional, multiple group, multiple-level IRT model estimation, evaluation, and scoring within a confirmatory modeling framework using marginal maximum likelihood (or, optionally, modal Bayes) estimation. From its initial release, flexMIRT has also been able to simulate data from any model it is able to estimate. As of Version 3.0, released in the summer of 2015, updates to the program have included an alternate estimation routine better suited for truly high-dimensional models, intuitive syntax for the estimation of diagnostic classification models, expanded capabilities to estimate exploratory factor analysis models with analytic rotations, and an allowance for models that include covariates predicting the latent variables.

flexMIRT is a syntax-driven program written in C++, meaning that any system that is able to compile the language is capable of running the flexMIRT statistical engine. A graphical user interface has been created for computers running Windows, which allows for some point-and-click functionality. For operational and research situations, such as testing companies scoring thousands of respondents in the real-time or simulation studies that require a large of number of repeated analyses, flexMIRT is also able to call through the command-line interface (e.g., Windows Command Prompt), either for an individual analysis or to run a batch file that automates the running of an unlimited number of existing syntax files.