It is common to assume during a statistical analysis of a multiscale assessment that the assessment is composed of several unidimensional subtests or that it has simple structure. Under this assumption, the unidimensional and multidimensional approaches can be used to estimate item parameters. These two approaches are equivalent in parameter…

Statistical prediction remains an important tool for decisions in a variety of disciplines. An equally important issue is identifying factors that contribute to more or less accurate predictions. The time series literature includes well developed methods for studying predictability and volatility over time. This article develops…

Results from 40 high school students on the mathematics subtest of the Scholastic Aptitude Test (SAT) support the prediction that successful students would have more prior knowledge and would be better at defining problems, assembling strategies, and avoiding computational errors. Results are discussed in terms of a cognitive processing model.…