In this ITEMS module, we provide a two-part introduction to the topic of reliability from the perspective of "classical test theory" (CTT). In the first part, which is directed primarily at beginning learners, we review and build on the content presented in the original didactic ITEMS article by Traub and Rowley (1991). Specifically, we…

Since Cronbach's (1951) elaboration of a from its introduction by Guttman (1945), this coefficient has become ubiquitous in characterizing assessment instruments in education, psychology, and other social sciences. Also ubiquitous are caveats on the calculation and interpretation of this coefficient. This article summarizes a recent contribution…

Brennan (Brennan, R. L., 2012) noted that users of test scores often want (indeed, demand) that subscores be reported, along with total test scores, for diagnostic purposes. Haberman (Haberman, S. J., 2008) suggested a method based on classical test theory (CTT) to determine if subscores have added value over the total score. According to this…

This article presents the author's observations on Neil Dorans's NCME Career Award Address: "The Contestant Perspective on Taking Tests: Emanations from the Statue within." He calls attention to some points that Dr. Dorans made in his address, and offers his thoughts in response.

Views on testing--its purpose and uses and how its data are analyzed--are related to one's perspective on test takers. Test takers can be viewed as learners, examinees, or contestants. I briefly discuss the perspective of test takers as learners. I maintain that much of psychometrics views test takers as examinees. I discuss test takers as a…

In this article, we discuss the importance of measurement literacy and some issues encountered in teaching introductory measurement courses. We present results from a survey of introductory measurement instructors, including information about the topics included in such courses and the amount of time spent on each. Topics that were included by the…

There is an increasing interest in reporting subscores, both at examinee level and at aggregate levels. However, it is important to ensure reasonable subscore performance in terms of high reliability and validity to minimize incorrect instructional and remediation decisions. This article employs a statistical measure based on classical test theory…

The authors describe the significant contributions of Robert Ebel to educational measurement theory and its applications. A biographical sketch details Ebel's roots and professional resume. His influence on classroom assessment views and procedures are explored. Classic publications associated with validity, reliability, and score interpretation…