This paper provides a history of ETS's role in developing assessment instruments and psychometric procedures for measuring change in large-scale national assessments funded by the Longitudinal Studies branch of the National Center for Education Statistics. It documents the innovations developed during more than 30 years of working with…

This study is an evaluation of the psychometric issues associated with estimating objective level scores, often referred to as "subscores." The article begins by introducing the concepts of reliability and validity for subscores from statewide achievement tests. These issues are discussed with reference to popular scaling techniques, classical…

This study uses a new psychometric model (mixture item response theory-MIMIC model) that simultaneously estimates differential item functioning (DIF) across manifest groups and latent classes. Current DIF detection methods investigate DIF from only one side, either across manifest groups (e.g., gender, ethnicity, etc.), or across latent classes…