Simplified formulas are proposed for computing the standard errors of equipercentile equating for continuous and discrete test scores. These formulas are easily extended to more complicated equating designs. Results from a study of 719 subjects taking an English test indicated that the formulas work reasonably well for moderate-size samples. (SLD)

Equating a new standard test to an old reference test is considered when samples for equating are not randomly selected from the target population of test takers, identifying two problems from equating from biased samples. An empirical example with data from the Armed Services Vocational Aptitude Battery illustrates the approach. (SLD)

It is a widely held belief that an anchor test used in equating should be a miniature version (or "minitest") of the tests to be equated; that is, the anchor test should be proportionally representative of the two tests in content and statistical characteristics. This paper examines the scientific foundation of this belief, especially…

Consistent behavior is a desirable characteristic that common items are expected to have when administered to different groups. Findings from the literature have established that items do not always behave in consistent ways; item indices and IRT item parameter estimates of the same items differ when obtained from different administrations.…

The LOGTRUE program can be used to obtain a scale of equated raw scores for two tests with parameter estimates on a common item response theory scale. The program derives its name from the method of logistic true score equating described by Lord (1980). The method can be applied to two tests with overlapping items administered to different groups…

This study considers the use of repeaters when test equating. The subjects consist of five groups of applicants to a professional certification program. Each group comprises first time examinees and repeaters. The procedures include a common item linear equating with nonrandom groups, use of equating chains, and the use of total examinee group…

This paper described one part of an item response theory (IRT) feasibility study performed for the Aptitude Test portion of the Graduate Record Examinations (GRE). The dimensionality of the GRE verbal and analytical sections is discussed. The results of six different types of equating of the verbal section and four different types of equating of…

The purpose of this study was to examine the homogeneity in difficulty of item domains and the effectiveness of Rasch pre-equating procedures for adjusting test scores for differences in the difficulty of tests constructed by sampling from item domains. The data used were taken from a field test and calibration of 810 tenth-grade items in…

Score equating requires that the forms to be equated are functionally parallel. That is, the two test forms should rank order examinees in a similar fashion. In language proficiency testing situations, this assumption is often put into doubt because of the numerous tests that have been proposed as measures of language proficiency and the…

One of a series of reports on the International Project for the Evaluation of Educational Achievement (in Mathmatics).

The central idea in building and maintaining an item bank is to calibrate all the items onto a "common variable." The arithmetic involved in the calibration process is presented. It is recommended that an analysis of fit be done in every application to verify that the estimates of item difficulties are in fact sample-free. These…

Three equating methods were compared in terms of magnitude of scale drift: equipercentile equating, linear equating, and item response theory (IRT) equating. A sample of approximately 2670 cases was selected for each pairing of a form of the Scholastic Aptitude Tests (SAT) and an anchor test. Of the two conventional equating methods,…

Issues concerning equating test scores are discussed in an introduction, four papers, and two commentaries. Equating methods research, sampling errors, linear equating, population differences, sources of equating errors, and a circular equating paradigm are considered. (SLD)

The analytical decomposition demonstrates how the effects of item characteristics, test properties, individual examinee responses, and rounding rules combine to produce the item deletion effect on the equating/scaling function and candidate scores. The empirical portion of the report illustrates the effects of item deletion on reported score…

Estimation techniques for generating the covariance matrix for two new tests and an existing test without the necessity of any examinee having to take two complete tests is presented. An application of these techniques to linear, observed-score, test equating is presented. (Author/JKS)