Item Response Theory

13Some Interesting Applications

Statistics is the most important science in the whole world, for upon it depends the practical application of every other (science) and of every art.

(Source: Florence Nightingale)

13.1 Introduction

While the majority of applications of item response theory (IRT) have been in educational measurement, with the advent of multidimensional item response theory (MIRT; (Bock and Aitkin 1981)) and computerized adaptive testing (CAT) (Kingsbury and Weiss 1980; Weiss 1985), there are many novel applications of IRT for the measurement of complex traits that go beyond the traditional application of IRT for unidimensional constructs that are the focus of application to educational measurement problems. In Sections 13.2–13.4, we consider several examples with the hope that these will stimulate much wider applications of the general theory.

13.2 Biobehavioral Synthesis

Stan et al. (2020) created a crosswalk between 51 clinician‐rated symptoms of psychosis and the cortical thickness of 68 regions of the brain, using a full‐information item bifactor model. While reduced cortical thickness has been found in psychotic disorders, prior to this, the relationship with cortical thickness in general and in specific regions of the brain, with specific psychotic symptoms had not been established. Specifically, they used MIRT to investigate whether there are specific ...