Item Response Theory and Rasch Modeling
Ralph J. De Ayala · 2018
Item response theory (IRT) is a psychometric modeling paradigm used for the measurement of psychological constructs. In its simplest form an IRT model contains a single continuous latent variable that represents the construct of interest (e.g., mathematics proficiency, depression, social anxiety), which in turn is believed to determine a person’s responses to a series of binary and/or polytomous questions. Both items and people are located on this continuous latent continuum. In general, a person’s location on this latent continuum is estimated as a function of his or her responses to those questions and the items’ location on the latent variable. From this basic model one can generalize to multiple latent construct variables that may be continuous or categorical and/or multiple item characterizations.