This paper discusses loglinear models for assessing differential item functioning (DIF). Loglinear and logit models that have been suggested for studying DIF are reviewed, and loglinear formulations of the logit models are given. A polynomial loglinear model for assessing DIF is introduced. Two examples using the polynomial loglinear model for…

Determining whether score distributions differ on two or more test forms administered to samples of examinees from a single population is explored using three statistical tests using loglinear models. Examples are presented of applying tests of distribution differences to decide if equating is needed for alternative forms of a test. (SLD)

Studied whether a group's average percent correct in a content domain could be accurately estimated for groups taking a single test form and not the entire domain of items. Evaluated six Item Response Theory-based domain score estimation methods through simulation and concluded they performed better than observed score on the form taken. (SLD)

Equating a test form to itself through a chain of equatings, commonly referred to as circular equating, has been widely used as a criterion to evaluate the adequacy of equating. This paper uses both analytical methods and simulation methods to show that this criterion is in general invalid in serving this purpose. For the random groups design done…

Presents a characteristic curve procedure for comparing transformations of the item response theory ability scale assuming the multiple-choice model. Illustrates the use of the method with an example equating American College Testing mathematics tests. (SLD)

The delta method was used to derive standard errors (SES) of the Levine observed score and Levine true score linear test equating methods using data from two test forms. SES derived without the normality assumption and bootstrap SES were very close. The situation with skewed score distributions is also discussed. (SLD)

This paper focuses on methodological issues in applying equipercentile equating methods to pairs of tests that do not meet the assumptions of equating. This situation is referred to as a concordance situation, as opposed to an equating situation, and the end result is a concordance table that gives "comparable" scores between the tests.…

Research studies using booklet classification were implemented by the American College Testing Program to investigate the linkage between the National Assessment of Educational Progress (NAEP) Achievement Levels Descriptions and the cutpoints set to represent student performance with respect to the achievement levels. This paper describes the…