Type I error rates and power were estimated for 10 tests of variance equality under various combinations of the following factors: similar and dissimilar distributional forms, equal and unequal means, and equal and unequal sample sizes. (TJH)

Item response theory equating invariance was examined by simulating vertical equating of two sets of examinee ability data comparing Rasch, three-parameter, and equipercentile equating methods. All three were reasonably invariant, suggesting that multidimensionality is likely to be the cause of lack of invariance found in real data sets. (SLD)

Item response theory (IRT) is having a major impact on the field of testing. This special issue presents an introduction and seven papers concerning developments in IRT applications. Some important IRT research being conducted outside the United States is highlighted. (SLD)

A computer simulation study was conducted to investigate the amount of uncertainty added to National Assessment of Educational Progress estimates by equating error under three different equating methods and while varying a number of factors that might affect accuracy of equating. Data from past NAEP administrations were used to guide the…

MAT and GRE scores were equated by regression, conditional mean, linear and equipercentile methods using data from a sample that had taken both tests. The regression and linear methods were preferred, and shown to be equivalent when the correlation between scales is perfect. (Author/RL)

A computer program providing comprehensive test and item analysis is presented. Completing its performance on one run, the program, written in Fortran and emphasizing ease of use, integrates various statistical techniques for analyzing individual items and the overall test, in addition to generating a variety of standard scores. (Author/JKS)

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)

Compared the observation of children's growth in reading using grade equivalents with that using the Rasch simultaneous vertical equating procedure. Results from equating 25 reading tests show that grade equivalents differ more between two different test forms than do ability measures obtained from the Rasch simultaneous vertical equating. (SLD)

Explored the feasibility of applying a method that incorporates collateral information to equate tests constructed for a college entrance examination by comparing its results with those of item response theory (IRT) true score equating. Simulation results suggest that, overall, equating results based on collateral information are relatively…

Studied five factors that can affect the equating of scores from two tests onto a common score scale through the simulation and equating of 4,860 item data sets. Findings indicate three statistically significant two-way interactions for common item length and test length, item difficulty standard deviation and item distribution type, and item…

The equating of results from the PC-BILOG computer program to an underlying metric was studied through simulation when a two-parameter item response theory model was used. Results are discussed in terms of the identification problem and implications for test equating. (SLD)

The effects of test item disclosure on resulting examinee equated scores and population passing rates were studied for 5,000 examinees taking a professional licensing examination. Results suggest that the effects of disclosing depended on the nature of the released items. Specific effects on particular examinees are also discussed. (SLD)

An Angoff method and a frequency estimation equipercentile equating method were compared, using data from three forms of a 200-item multiple-choice certification test. Data requirements are fewer and computational requirements less burdensome for the former than for the latter method. However, results of the two methods are not interchangeable.…

A numerical approach for computing standard errors (SEs) of a linear equating is described in which first partial derivatives of equating functions needed to compute SEs are derived numerically. Numerical and analytical approaches are compared using the Tucker equating method. SEs derived numerically are found indistinguishable from SEs derived…

Discusses the comparison of groups of individuals who were administered different forms of a test. Focuses on the situation in which there is little overlap in content between the test forms. Reviews equating problems in national tests in Canada and Israel. (SLD)