Unidimensional Item Response Theory Models

Abstract

In Chap. 3, the point will be made that multidimensional item response theory (MIRT) is an outgrowth of both factor analysis and unidimensional item response theory (UIRT). Although this is clearly true, the way that MIRT analysis results are interpreted is much more akin to UIRT. This chapter provides a brief introduction to UIRT with a special emphasis on the components that will be generalized when MIRT models are presented in Chap. 4. This chapter is not a thorough description of UIRT models and their applications. Other texts such as Lord (1980), Hambleton and Swaminathan (1985), Hulin et al. (1983), Fischer and Molenaar (1995), and van der Linden and Hambleton (1997) should be consulted for a more thorough development of UIRT models.