Module 31: Scaling

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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 information into a score scale, and introduces vertical scaling and its related designs and methodologies as a special type of scaling. After completion of this module, the reader should be able to understand the relationship between various types of raw scores, understand the relationship between raw scores and scale scores, construct a scale with desired properties, evaluate an existing score scale, understand how content and standards information are built into a scale, and understand how vertical scales are developed and used in practice.

Keywords: item response theory, IRT, linear transformation, nonlinear transformation, raw score, scale score, scaling, score precision, score reporting, vertical scaling

Ye Tong

Vice President, Pearson, Boston

Michael J. Kolen

Professor of Educational Measurement, University of Iowa, Iowa City, IA

Michael J. Kolen is a Professor of Educational Measurement at the University of Iowa. Dr. Kolen received his doctorate from the University of Iowa in 1979, his MA degree from the University of Arizona in 1975, and his BS degree from the University of Iowa in 1973. He served on the faculty at Hofstra University from 1979-1981, and he worked at American College Testing (ACT) from 1981-1997, including being Director of the Measurement Research at ACT from 1990-1997.

Dr. Kolen co-authored the book Test Equating: Methods and Practices, published by Springer-Verlag. He has published numerous articles and book chapters on various topics in educational measurement and statistics, including test equating and scaling.

Dr. Kolen has been President of the National Council on Measurement in Education (NCME), and is past editor of the Journal of Educational Measurement. He is a Fellow of Division 5 of the American Psychological Association, a Fellow of the American Educational Research Association, and member of various other professional organizations. Dr. Kolen received the 1997 NCME Award for Outstanding Technical Contribution to the Field of Educational Measurement and the 2008 NCME Award for Career Contributions of Educational Measurement.


Module 31: Scaling: An ITEMS Module
Open to download resource.
Open to download resource.