The Item Analysis platform enables you to fit item response theory models. The Item Response Theory (IRT) method is used for the analysis and scoring of measurement instruments such as tests and questionnaires. Item response theory uses a system of models to relate a trait or ability to an individual’s probability of endorsing or correctly responding to an item. Frequently, the trait or ability of interest is not directly measurable and is therefore called latent. IRT can be used to study standardized tests, cognitive development, and consumer preferences. IRT is an alternative method to classical test theory (CTT) where the focus is on the total observed score rather than the item scores.
Figure 9.1 Item Analysis Characteristic Plot

Help created on 7/12/2018