Current procedures for equating number-correct scores using traditional item response theory (IRT) methods assume local independence. However, when tests are constructed using testlets, one concern is the violation of the local item independence assumption. The testlet response theory (TRT) model is one way to accommodate local item dependence.…

The traditional way of equating the scores on a new test form X to those on an old form Y is equipercentile equating for a population of examinees. Because the population is likely to change between the two administrations, a popular approach is to equate for a "synthetic population." The authors of the articles in this issue of the…

Personal construct psychologists have suggested various psychological functions explain differences in the stability of constructs. Among these functions are constellatory and loose construction. This paper argues that measurement error is a more parsimonious explanation of the differences in construct stability reported in these studies. (Author)

Two estimation procedures for the Rasch Model of test analysis are reviewed in detail, particularly with respect to new developments that make the more statistically rigorous conditional maximum likelihood estimation practical for use with longish tests. (Author/JKS)

An attempt was made to determine which item response theory (IRT) equating method results in the least amount of equating error or "scale drift" when equating scores across one or more test forms. An internal anchor test design was employed with five different test forms, each consisting of 30 items, 10 in common with the base test and 5…

Two local methods for observed-score equating are applied to the problem of equating an adaptive test to a linear test. In an empirical study, the methods were evaluated against a method based on the test characteristic function (TCF) of the linear test and traditional equipercentile equating applied to the ability estimates on the adaptive test…

Two approaches to criterion-referenced test construction are compared. Classical test theory is based on the practice of random sampling from a well-defined domain of test items; latent trait theory suggests that the difficulty of the items should be matched to the achievement level of the student. In addition to these two methods of test…

Context effects are defined as being influences on test performance associated with the content of successively presented test items or sections. Four types of context effects are identified: (1) direct context effects (practice effects) which occur when performance on items is affected by the examinee having been exposed to similar types of…