Three potential causes of scale shrinkage (measurement error, restriction of range, and multidimensionality) in item response theory vertical equating are discussed, and a more comprehensive model-based approach to establishing vertical scales is described. Test data from the National Assessment of Educational Progress are used to illustrate the…

In this article, the history of linking is summarized, and current linking frameworks that have been proposed are considered. Key publications discussed include Flanagan (1951), Angoff (1971), Linn (1993), Mislevy (1992), and Feuer, Holland, Green, Bertenthal, and Hemphill (1999). The article further focuses on the concordance situation for…

The influence of anchor length on the accuracy of test equating was studied using Tucker's linear method and two Item-Response-Theory (IRT) based methods, focusing on whether equating accuracy improved with more anchor items, whether the anchor effect depended on the equating method used, and the adequacy of the inclusion of the guessing parameter…

Equating multiple test forms is frequently desired. When multiple forms are linked in a chain of equating, error tends to build up in the process. This paper compares three procedures for equating multiple forms in a common-form design where each school administered, in a spiraled fashion, only a subset of multiple forms. Data used were from a…

Applications of item response theory to practical testing problems including equating, differential item functioning, and computerized adaptive testing, require that item parameter estimates be placed onto a common metric. In this study, two methods for developing a common metric for the graded response model under item response theory were…

Modern applications of computerized adaptive testing (CAT) are typically grounded in item response theory (IRT; Lord, 1980). While the IRT foundations of adaptive testing provide a number of approaches to adaptive test scoring that may seem natural and efficient to psychometricians, these approaches may be more demanding for test takers, test…

This paper summarizes an investigation of the format used for equating the 1993 Illinois Goal Assessment Program (IGAP) sixth grade reading test. In 1992, each student took only one test, either a narrative test or an expository test. In 1993, there was only one test, which included both formats. Several possible approaches for linking the 1993…

Equating studies using item response theory (IRT) are reviewed. The most well-known papers, as well as a sampling of lesser-known studies, are included. Accompanying tables list the papers and classify them according to the test used, models used, test length and type, sample size and type, method of assessment, equating design, and kinds of…

Research on military reading abilities has shown a direct relationship between reading ability and training and job performance. The objectives of this study of the development of a reading scale were to: (1) measure the reading ability of military applicants using six commonly used reading tests; (2) use the Armed Services Vocational Aptitude…

The purpose of this study was twofold: to investigate to what extent characteristics of anchor tests may affect precision of item calibration, and to estimate to what extent precision of item calibration may be affected by removal of persons whose response patterns deviate from those normally expected from the Rasch one-parameter logistic model.…

The accuracy of trait estimates obtained from three vertical equating methods was examined. The procedures studied included two anchor test designs and a single-group design. Data from two content areas and two grade combinations were studied. A three-parameter logistic model was used to perform the equatings. The results obtained were used to…

Unidimensional item response theory (IRT) is widely used in the analysis and equating of educational achievement tests. If an IRT model is true, item response must be locally independent when the trait is held constant. Several measures of local dependence which are used in conjunction with the three-parameter logistic model in the analysis of…

In January 1982, the College Board and Educational Testing Service implemented a technical change in the procedures used to equate scores on the Scholastic Aptitude Test (SAT). For previous editions of the SAT, a linear equating procedure was used to establish the comparability of scores on different editions. Beginning in January 1982, this…

THIRTY-SIX COLLEGE FRESHMEN WERE MATCHED FOR MATH ABILITY AND RANDOMLY ASSIGNED TO AN EXPERIMENTAL AND CONTROL GROUP, TO WORK A 71-ITEM LINEAR PROGRAM IN SCRAMBLED AND ORDERED SEQUENCE, RESPECTIVELY. AN IMMEDIATE POST-TEST SHOWED THAT--ITEM SEQUENCE HAD NO SIGNIFICANT EFFECT ON LEARNING TIME, ERROR SCORE, TEST SCORE, OR TEST TIME. PRIOR MATH…

In order to determine the comparability of the IQ estimates and subtest scores on the Wechsler Intelligence Scale for Children (WISC) and the Wechsler Intelligence Scale for Children--Revised, both tests were adminstered in a four-cell counter-balanced design. Overlapping items were given only once. Subjects were 77 male and 51 female adolescents…