ABSTRACT
Item response theory (IRT) is a psychometric modeling paradigm used for the measurement of psychological constructs that is typically based on continuous latent variables. 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 persons’ 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 and/or multiple item characterizations.
