Classical test theory is based on the concept of a true score for each examinee, defined as the expected or average score across an infinite number of repeated parallel tests. In most cases, there is only a score from a single administration of the test in question. The difference between this single observed score and the underlying true score is…

This study compared various equating models and procedures for a sample of data from the Medical College Admission Test(MCAT), considering how item response theory (IRT) equating results compare with classical equipercentile results and how the results based on use of various IRT models, observed score versus true score, direct versus linked…

Presented are the methodology and results of an equipercentile equating study in which subtests of the following three editions of multiple aptitude test batteries, in widespread use in 1960, were equated to the tests of the Project TALENT test battery: Flanagan Aptitude Classification Tests (1957); Differential Aptitude Tests (1947) and; the…

This study investigated the practical effects of local item dependence (LID) on item response theory (IRT) true-score equating. A scenario was defined that emulated the Law School Admission Test (LSAT) preequating model, and data were generated to assess the impact of different degrees of LID on final equating outcomes. An extreme amount of LID…

Four equating methods were compared using four equating criteria: first-order equity (FOE), second-order equity (SOE), conditional mean squared error (CMSE) difference, and the equipercentile equating property. The four methods were: (1) three parameter logistic (3PL) model true score equating; (2) 3PL observed score equating; (3) beta 4 true…

Multidimensionality is known to affect the accuracy of item parameter and ability estimations, which subsequently influences the computation of item characteristic curves (ICCs) and true scores. By judiciously combining sections of a Law School Admission Test (LSAT), 11 sections of varying degrees of uni- and multidimensional structures are used…

Procedures are described for studying the reliability of decisions based on specific passing scores with tests made up of discrete items and designed to measure continuous rather than categorical traits. These procedures are based on the estimation of the joint distribution of true scores and observed scores. (CTM)

The feasibility of pre-equating, or establishing conversions from raw to scaled scores through the use of pretest data before operationally administering a test, was investigated for the Scholastic Aptitude Test (SAT). Item-response theory based equating methods were used to estimate item parameters on SAT pretest data, instead of using final form…