The evaluation of intervention effects is an important objective of educational research. One way to evaluate the effectiveness of an intervention is to conduct an experiment that assigns individuals to control and treatment groups. In the context of pretest/posttest designed studies, this is referred to as a control-group pretest/posttest design.…

In many testing programs it is assumed that the context or position in which an item is administered does not have a differential effect on examinee responses to the item. Violations of this assumption may bias item response theory estimates of item and person parameters. This study examines the potentially biasing effects of item position. A…

The purpose of this study was to examine the performance of differential item functioning (DIF) assessment in the presence of a multilevel structure that often underlies data from large-scale testing programs. Analyses were conducted using logistic regression (LR), a popular, flexible, and effective tool for DIF detection. Data were simulated…

Although response times on test items are recorded on a natural scale, the scale for some of the parameters in the lognormal response-time model (van der Linden, 2006) is not fixed. As a result, when the model is used to periodically calibrate new items in a testing program, the parameter are not automatically mapped onto a common scale. Several…

This article presents a non-mathematical introduction to latent trait test models and some of their features. Latent trait models are compared to classical test models. Two promising applications of latent trait models and available computer programs are discussed. (Author/JKS)

This article explains the Rasch model for sample-free item analysis and test-free person measurement. It shows how to estimate model parameters from data and how to evaluate the statistical fit of these estimates to the data. Attention is paid to practical considerations. (Author/JKS)

Special emphasis is given to the kinds of control that can be exercised over initial status, including the use of proxy input data. A rationale for the classification scheme is developed, based on (1) three one-shot, one cross-sectional, and two longitudinal data types and (2) two types of referencing: criterion referencing and norm referencing.…

A variety of practical applications of item characteristic curve test theory are discussed. Among these applications are tailored testing, two stage testing, determining whether two tests measure the same latent trait, and measuring item bias towards minority or other groups. (Author/JKS)

Article is concerned with a model for school system evaluation. The usefulness of the indices from this model depend on their stability, and this study presents evidence related to their stability when pupils and factors related to time are considered as sources of error. (Author/RK)

Measurement scales developed using Thurstone and item-response theory (IRT) methods of scaling achievement tests for the same single-level data were compared for approximately 4,000 high school students taking the Iowa Tests of Educational Development in 1975. Results of both approaches indicate that variability increases as grade level increases.…