Module Overview: In this digital ITEMS module, Dr. Jodi M. Casabianca provides a primer on the "hierarchical rater model" (HRM) framework and the recent expansions to the model for analyzing raters and ratings of constructed responses. In the first part of the module, she establishes an understanding of the nature of constructed…

Studies investigating invariance have often been limited to measurement or prediction invariance. Selection invariance, wherein the use of test scores for classification results in equivalent classification accuracy between groups, has received comparatively little attention in the psychometric literature. Previous research suggests that some form…

Simulation studies are extremely common in the item response theory (IRT) research literature. This article presents a didactic discussion of "truth" and "error" in IRT-based simulation studies. We ultimately recommend that future research focus less on the simple recovery of parameters from a convenient generating IRT model,…

"Scaling" is the process of constructing a score scale that associates numbers or other ordered indicators with the performance of examinees. Scaling typically is conducted to aid users in interpreting test results. This module describes different types of raw scores and scale scores, illustrates how to incorporate various sources of…

TESTAT is a supplementary module for the popular SYSTAT statistical package for the personal computer. The program performs test analyses based on classical test theory and item response theory. Limitations and advantages are discussed. (SLD)