A Review of Developments and Applications in Item Analysis
Methodology of Educational Measurement and Assessment
This chapter summarizes contributions ETS researchers have made concerning the applications of, refinements to, and developments in item analysis procedures. The focus is on dichotomously scored items, which allows for a simplified presentation that is consistent with the focus of the developments and which has straightforward applications to polytomously scored items. Item analysis procedures refer to a set of statistical measures used by testing experts to review and revise items, to estimate
... items, to estimate the characteristics of potential test forms, and to make judgments about the quality of items and assembled test forms. These procedures and statistical measures have been alternatively characterized as conventional item analysis (Lord 1961 (Lord , 1965a , traditional item analysis (Wainer 1989), analyses associated with classical test theory (Embretson and Reise 2000; Hambleton 1989; Tucker 1987; Yen and Fitzpatrick 2006) , and simply item analysis (Gulliksen 1950; Livingston and Dorans 2004) . This chapter summarizes key concepts of item analysis described in the sources cited. The first section describes item difficulty and discrimination indices. Subsequent sections review discussions about the relationships of item scores and test scores, visual displays of item analysis, and the additional roles item analysis methods have played in various psychometric contexts. The key concepts described in each section are summarized in Table 2 .1.