Journal of Early Adolescence XX(X) 1–32 © The Author(s) 2013 Reprints and permissions: sagepub.com/journalsPermissions.nav DOI: 10.1177/0272431613511332 jea.sagepub.com Article Practical Guide to Conducting an Item Response Theory Analysis Michael D. Toland 1 Abstract Item response theory (IRT) is a psychometric technique used in the development, evaluation, improvement, and scoring of multi-item scales. This pedagogical article provides the necessary information needed to understand how to conduct, interpret, and report results from two commonly used ordered polytomous IRT models (Samejima’s graded response [GR] model and reduced GR model). Throughout this article, simulated data from a multi-item scale is used to illustrate IRT analyses. The simulated data and IRTPRO version 2.1 point-and-click commands needed to reproduce all analyses in this article are available as supplemental online materials at http:// jea.sagepub.com/maint. The intent of this article is to provide an overview of essential components of an IRT analysis to enable increased access to this powerful tool for applied early adolescence researchers. Keywords item response theory, pedagogical, IRTPRO Constructing a psychometrically appropriate multi-item scale to measure a latent trait variable (such as general perceived self-efficacy, subjective well- being, or emotional intelligence) entails the collaboration of content experts, 1 University of Kentucky, Lexington, USA Corresponding Author: Michael D. Toland, Department of Educational, School, and Counseling Psychology, University of Kentucky, 243 Dickey Hall, Lexington, KY 40506, USA. Email: toland.md@uky.edu 511332JEA XX X 10.1177/0272431613511332Journal of Early AdolescenceToland research-article 2013 by guest on February 9, 2016 jea.sagepub.com Downloaded from