Stewart questioned Beglar's use of Rasch analysis of the Vocabulary Size Test (VST) and advocated the use of 3-parameter logistic item response theory (3PLIRT) on the basis that it models a non-zero lower asymptote for items, often called a "guessing" parameter. In support of this theory, Stewart presented fit statistics derived from…

It has been demonstrated that corrected-for-guessing scores will be superior to number-right scores in providing estimates of examinee standing on the trait measured by a multiple-choice test, if it can be assumed that examinees can and will comply with the appropriate directions. The purpose of the present study was to test the validity of that…

This study empirically determined the optimizing weight to be applied to the Wrongs Total Score in scoring rubrics of the general form = R - kW, where S is the Score, R the Rights Total, k the weight and W the Wrongs Total, if reliability is to be maximized. As is well known, the traditional formula score rests on a theoretical framework which is…

While most school districts believe they understand grade equivalent scores, teachers, parents, and measurement specialists frequently misinterpret this apparently simple statistical expression. Echternacht's article describes the construction, application, and interpretation of grade equivalent scores from the test publisher's perspective.…

This primer is an introduction to item response theory (also called item characteristic curve theory, or latent trait theory) as it is used most commonly--for scoring multiple choice achievement or aptitude tests. Written for the testing practitioner with minimum training in statistics and psychometrics, it presents and illustrates the basic…