Classical test theory is founded on the proposition that measurement error, a random latent variable, is a component of the observed score random variable. This article traces the history of the development of classical test theory, beginning in the early 20th century. (SLD)

The accuracy of statistics based on performance assessments that represent percentages of students reaching standards is explored using data from a large-scale performance assessment, the Maryland School Performance Assessment Program. Results with students in grades 3, 5, and 8 support the accuracy of pooling results to produce the statistics.…

The application of generalizability theory to the reliability and error variance estimation for performance assessment scores is discussed. Decision makers concerned with performance assessment need to realize the restrictions that limit generalizability such as limitations that lead to reductions in the number of tasks possible, rater quality,…

This paper discusses standard error of measurement (SEM), the amount of variation or spread in the measurement errors for a test, and gives information needed to interpret test scores using SEMs. SEMs at various score levels should be used in calculating score bands rather than a single SEM value. (SLD)

We contend that generalizability (G) theory allows the design of psychometric approaches to testing English-language learners (ELLs) that are consistent with current thinking in linguistics. We used G theory to estimate the amount of measurement error due to code (language or dialect). Fourth- and fifth-grade ELLs, native speakers of…