Modern test theory
Modern test theory models are techniques to assess the psychometric characteristics of an instrument, focused on the dimensionality of the questionnaire 5,25. It provides item-specific information and avoids weight bias owing to subjective allocation of each item (also known as differential item functioning)5,25.
IRT is composed of associated mathematical models that models the relation between the latent trait and the item responses26. IRT examines latent trait estimates that do not vary with the characteristics of the population, also, estimates item difficulty and discrimination, and determines if response categories are ordered properly and function as intended 27.