Cliff's Index "c" derived from an item dominance matrix is utilized in a clustering approach, termed extracting Reliable Guttman Orders (ERGO), to isolate Guttman-type item hierarchies. A comparison of factor analysis to the ERGO is made on social distance data involving multiple ethnic groups. (Author/BW)

A strategy for overcoming problems with the Rasch model's inability to handle missing data involves a pairwise algorithm which manipulates the data matrix to separate out the information needed for the estimation of item difficulty parameters in a test. The method of estimation compares two or three items at a time, separating out the ability…

After tests are administered, they are scored and the scores are given back to the students. If the real purpose of the test is to improve student learning, simply returning the scores is not sufficient. The first step in evaluating test results is to be sure that the test has tested the intended concepts and content. Calculating the mean and the…