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Updated: Jul 7, 2026

Qualitative and Quantitative Validation of Tools with Rating Scales Aimed at Assessing the Quality of University Service-Learning
Published on: August 29, 2025
Using the cumulative common log-odds ratio to identify differential item functioning of rating scale items in the
Randall D Penfield1, Peter R Giacobbi, Nicholas D Myers
1Department of Educational and Psychological Studies, University of Miami, Coral Gables, FL 33124-2040, USA. penfield@miami.edu
Abstract:
One aspect of construct validity is the extent to which the measurement properties of a rating scale are invariant across the groups being compared. An increasingly used method for assessing between-group differences in the measurement properties of items of a scale is the framework of differential item functioning (DIF). In this paper we introduce the concept of DIF as a validation tool for scales used in physical education and exercise science, and illustrate the use of the cumulative common log-odds ratio for assessing the presence of DIF with data from the Exercise Imagery Inventory (EII; Giacobbi, Hausenblas, & Penfield, 2005).
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