Item response theory (IRT) uses a family of statistical models for estimating stable characteristics of items and examinees and defining how these characteristics interact in describing item and test performance. With a focus on the three-parameter logistic IRT (Birnbaum, 1968; Lord, 1980) model, the current study examines the accuracy and…

Small sample equating remains a largely unexplored area of research. This study attempts to fill in some of the research gaps via a large-scale, IRT-based simulation study that evaluates the performance of seven small-sample equating methods under various test characteristic and sampling conditions. The equating methods considered are typically…

The purpose of this paper is to highlight some psychometric cautions that should be observed when seeking to develop short form versions of tests. Several points are made: (1) score reliability is impacted directly by the characteristics of the sample and testing conditions; (2) sampling error has a direct influence on reliability and factor…

Situations in which mailed questionnaires are most appropriate are identified. Population variables, characteristics of questionnaires, and social desirability variables are examined in depth. (Author)