Item Response Theory
Item Response Theory is a system of models that define a correspondence between latent variables (unidimensional continuum construct) and their manifestations (items).
Focus of interest: Item-Level
Item-Type: Dichotomous and Ordered or Unordered Polytomous Items
Latent Trait (theta): Continuous and Normally Distribuited
Error term: It varies across items and latent trait
Item Response Function Shape: Sigmoid-Shape
