Statistical Descriptions of Item and Test Functioning

Abstract

The MIRT models in Chap. 4 provide mathematical descriptions of the interactions of persons and test items. Although the parameters of these models summarize the characteristics of the items, the vectors of item parameters sometimes lack intuitive meaning. This chapter provides other statistical ways of describing the functioning of test items that may more clearly indicate the value of the test items for determining the location of individuals in the multidimensional θ-space. The ways of describing test item characteristics given here are direct extensions of the descriptive information for UIRT models described in Chap. 2.