Growth across Grades and Common Item Grade Alignment in Vertical Scaling Using the Rasch Model
Date
2024-11-25
Journal Title
Journal ISSN
Volume Title
Publisher
Educational Measurement: Issues and Practice
Abstract
Vertical scales are frequently developed using common item nonequivalent group linking. In this design, one can use upper-grade, lower-grade, or mixed-grade common items to estimate the linking constants that underlie the absolute measurement of growth. Using the Rasch model and a dataset from Curriculum Associates’ i-Ready Diagnostic in math in grades 3–7, we demonstrate how grade-to-grade mean differences in mathematics proficiency appear much larger when upper-grade linking items are used instead of lower-grade items, with linkings based on a mixture of items falling in between. We then consider salient properties of the three calibrated scales including invariance of the different sets of common items to student grade and item difficulty reversals. These exploratory analyses suggest that upper-grade common items in vertical scaling are more subject to threats to score comparability across grades, even though these items also tend to imply the most growth.
Description
This is the peer reviewed version of the following article: Student, S.R., Briggs, D.C. and Davis, L. (2025), Growth across Grades and Common Item Grade Alignment in Vertical Scaling Using the Rasch Model. Educational Measurement: Issues and Practice, 44: 84-95. https://doi.org/10.1111/emip.12639, which has been published in final form at https://doi.org/10.1111/emip.12639. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited.
© 2024 by the National Council on Measurement in Education.
This article will be embargoed until 11/25/2026.
Keywords
invariance, linking
Citation
Student, S.R., Briggs, D.C. and Davis, L. (2025), Growth across Grades and Common Item Grade Alignment in Vertical Scaling Using the Rasch Model. Educational Measurement: Issues and Practice, 44: 84-95. https://doi.org/10.1111/emip.12639