Assessed multidimensionality for six forms of the Law School Admission Test (LSAT) through factor analysis. Determined that the LSAT appears to measure two different reasoning abilities: inductive and deductive. Describes the techniques used to assess dimensionality. (SLD)

The Non-Equivalent-groups Anchor Test (NEAT) design has been in wide use since at least the early 1940s. It involves two populations of test takers, P and Q, and makes use of an anchor test to link them. Two linking methods used for NEAT designs are those (a) based on chain equating and (b) that use the anchor test to post-stratify the…

This article describes a new, unified framework for linear equating in a non-equivalent groups anchor test (NEAT) design. The authors focus on three methods for linear equating in the NEAT design--Tucker, Levine observed-score, and chain--and develop a common parameterization that shows that each particular equating method is a special case of the…

Educational measurement practitioners are often asked to link scores on tests that are built to different content specifications. The goal in linking distinct tests is often similar to that for equating scores across different forms of the same test: to provide a set of comparable scores across the two measures. Traditional equating methods can be…

This study applied kernel equating (KE) in two scenarios: equating to a very similar population and equating to a very different population, referred to as a distant population, using SAT® data. The KE results were compared to the results obtained from analogous classical equating methods in both scenarios. The results indicate that KE results are…

Population invariance is an important requirement of test equating. An equating function is said to be population invariant when the choice of (sub)population used to compute the equating function does not matter. In recent studies, the extent to which equating functions are population invariant is typically addressed in terms of practical…

A special case of examinee choice, the Optional Essay Problem, is examined from the point of view of test equating. The Optional Essay Problem involves equating essay scores when the examinees are required to select an optional essay topic from a list of topics in addition to taking a mandatory test required of all examinees. The conditions that…

Kernel equating is a method of equating test scores devised by P. W. Holland and D. T. Thayer (1989). It takes its name from kernel smoothing, a process of smoothing a function by replacing each discrete value with a frequency distribution. It can be used when scores on two forms of a test are to be equated directly or when they are to be equated…

Two recent simulation studies were conducted to aid in the diagnosis and interpretation of equating differences found between random and matched (nonrandom) samples for four commonly used equating procedures: (1) Tucker; (2) Levine equally reliable; (3) Chained equipercentile observed-score; and (4) three-parameter, item response theory true-score…

The effects of anchor test characteristics in the accuracy and precision of test equating in the "common items, nonequivalent groups design" were studied. The study also considered the effects of nonparallel based and new forms on the equating solution, and it investigated the effects of differential weighting on the success of equating…

In 1955, R. Levine introduced two linear equating procedures for the common-item non-equivalent populations design. His procedures make the same assumptions about true scores; they differ in terms of the nature of the equating function used. In this paper, two parameterizations of a classical congeneric model are introduced to model the variables…

Large sample standard errors for the Tucker method of linear equating under the common item nonrandom groups design are derived under normality assumptions as well as under less restrictive assumptions. Standard errors of Tucker equating are estimated using the bootstrap method described by Efron. The results from different methods are compared…

The purpose of this study was to empirically examine the relationship between violations of the assumption of unidimensionality, as assessed by the factor analysis of item parcel data, and the quality of item response theory (IRT) true-score equating, as measured by score scale stability. The verbal section of the Scholastic Aptitude Test (SAT)…

A formula is derived for the asymptotic standard error of a true-score equating by item response theory (IRT). The equating method is applicable when the two tests to be equated are administered to different groups along with an "anchor test." Numerical standard errors are shown for an actual equating 1) comparing the standard errors of…