In this article, we present a theory of test translation whose intent is to provide the conceptual foundation for effective, systematic work in the process of test translation and test translation review. According to the theory, translation error is multidimensional; it is not simply the consequence of defective translation but an inevitable fact…

Spearman's factor-analytic model has been proposed as a unidimensional linear item response theory (IRT) model for continuous item responses. This article first proposes a reexpression of the model that leads to a form similar to that of standard IRT models for binary responses and discusses the item indices of difficulty discrimination and…

As item response models gain increased popularity in large-scale educational and measurement testing situations, many studies have been conducted on the development and applications of unidimensional and multidimensional models. Recently, attention has been paid to IRT-based models with an overall ability dimension underlying several ability…

The purpose of this study was to identify and validate items applicable to evaluating online courses at the postsecondary level. Items were derived from a review of the literature. Four judges rated the similarity of the items by making pair-wise comparisons utilizing multidimensional scaling (MDS). The study consisted of five stages. Stage I…

This study linked nonlinear profile analysis (NPA) of dichotomous responses with an existing family of item response theory models and generalized latent variable models (GLVM). The NPA method offers several benefits over previous internal profile analysis methods: (a) NPA is estimated with maximum likelihood in a GLVM framework rather than…

Investigated the usefulness of multidimensional scaling (MDS) for assessing the dimensionality of dichotomous test data. Focused on two MDS proximity measures, one based on the PC statistic (T. Chen and M. Davidson, 1996) and other, on interitem Euclidean distances. Simulation results show that both MDS procedures correctly identify…

The G index of agreement does not permit the use of various weights for its various items. The weighted G index described here, make it possible to use unequal weights. An example of the procedure is provided. (Author/JKS)

Introduces a new approach for partitioning test items into dimensionally distinct item clusters. The core of this approach is a new item-pair conditional-covariance-based proximity measure that can be used with hierarchical cluster analysis. The procedure can correctly classify, on average, over 90% of the items for correlations as high as 0.9.…

Generalizations of the G index as a measure of similarity between persons beyond the dichotomous situation are discussed. An attempt is made to present a generalization that does not require dichotomization of the items for cases where the number of response alternatives may differ. (Author/JKS)

The valid provision of subscores from an item response theory-based test implies a multidimensional test structure. Assuming, in the construction of a new test, that the test features required for a valid and reliable total test score have been specified already, this article describes the resulting subscore performance and the resulting…

Describes content-validity theory and illustrates new and traditional approaches for conducting content-validity studies. Newer approaches are based on multidimensional scaling analysis of item-similarity ratings, while traditional approaches are based on ratings of item-objective congruence and relevance. (Author/SLD)

In this paper I describe and illustrate the Roussos-Stout (1996) multidimensionality-based DIF analysis paradigm, with emphasis on its implication for the selection of a matching and studied subtest for DIF analyses. Standard DIF practice encourages an exploratory search for matching subtest items based on purely statistical criteria, such as a…

The purpose of this paper is to present a generalization of the concept of item difficulty to test items that measure more than one dimension. Three common definitions of item difficulty were considered: the proportion of correct responses for a group of individuals; the probability of a correct response to an item for a specific person; and the…

The purpose of this paper is to examine the capabilities of various procedures for sorting dichotomously-scored items into unidimensional subjects. The procedures include: factor analysis, nonmetric multidimensional scaling, cluster analysis, and latent trait analysis. Both simulated and real data sets of known structure were used to evaluate the…

The consequences of using item response theory (IRT) item bias detecting procedures with multidimensional IRT item data are examined. Limitations in procedures for detecting item bias are discussed. (SLD)