Changes to state tests impact the ability of State Education Agencies (SEAs) to monitor change in performance over time. The purpose of this study was to evaluate the Standardized Performance Growth Index (PGIz), a proposed statistical model for measuring change in student and school performance, across transitions in tests. The PGIz is a…

The closed-interval signed area (CSA) and closed-interval unsigned area (CUA) statistics were studied by Monte Carlo simulation to detect differential item functioning (DIF) when the reference and focal groups had different parameter distributions. Different behaviors of the CSA and CUA as functions of the parameters are discussed. (SLD)

Simulated data are used to assess the appropriateness of using separate calibration and between-fit approaches to detecting item bias in the Rasch rating scale model. Results indicate that Type I error rates for the null distribution hold even when there are different ability levels for reference and focal groups. (SLD)