An Introduction to Using Multidimensional Item Response Theory to Assess Latent Factor Structures

This study provides an introduction to the use of multidimensional item response theory (MIRT) analysis for assessing latent factor structure, and compares this statistical technique to confirmatory factor analysis (CFA) in the evaluation of an original measure developed to assess students’ motivations for entering a social work community of practice. The Participation in a Social Work Community of Practice Scale (PSWCoP) was administered to 506 masters of social work students from 11 accredited graduate programs. The psychometric properties and latent factor structure of the scale are evaluated using MIRT and CFA techniques. Although designed as a 3-factor measure, analysis of model fit using both CFA and MIRT do not support this solution. Instead, analyses using both methods produce convergent results supporting a 4-factor solution. Discussion includes methodological implications for social work research, focusing on the extension of MIRT analysis to assessment of measurement invariance in differential item functioning, differential test functioning, and differential factor functioning.