ABSTRACT
Editor Introduction: This chapter places the models developed in later chapters into a common historical context. The authors review dichotomous IRT models and lay an important foundation for the concept of information—a key concept in IRT. They also discuss nonparametric IRT and provide an introduction to the issue of parameter estimation. This provides an excellent starting point from which to delve deeper into the specific models, issues surrounding these models, and uses of the models that are provided in later chapters.
