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Updated: Mar 2, 2026

Qualitative and Quantitative Validation of Tools with Rating Scales Aimed at Assessing the Quality of University Service-Learning
Published on: August 29, 2025
How to reduce the number of rating scale items without predictability loss?
W W Koczkodaj1, T Kakiashvili2, A Szymańska3
1Computer Science, Laurentian University, 935 Ramsey Lake Rd., Sudbury, ON P3E 2C6 Canada.
This study introduces a novel method using the area under the receiver operator curve (AUC ROC) to reduce rating scale items, significantly cutting data collection needs without losing predictability for qualitative research.
Area of Science:
- Psychometrics
- Quantitative Psychology
- Research Methodology
Background:
- Rating scales are crucial for collecting data on qualitative constructs.
- Existing scales can be lengthy, leading to data redundancy and collection inefficiencies.
Purpose of the Study:
- To present an innovative method for reducing the number of items in rating scales.
- To demonstrate that item reduction does not compromise data predictability or scale reliability.
Main Methods:
- The study employed the area under the receiver operator curve (AUC ROC) method for item reduction.
- Statistical validation was performed using the Graded Response Model (GRM) and Confirmatory Factor Analysis (CFA).
Main Results:
- The AUC ROC method reduced rating scale items by over 70% (from 21 to 6 variables).
- The Graded Response Model confirmed the reduced scale's ability to differentiate between high and middle scores.
- Confirmatory Factor Analysis verified that scale reliability was maintained post-reduction.
Conclusions:
- The AUC ROC method offers an effective approach to data reduction in rating scales.
- This method enhances research efficiency by minimizing unnecessary data collection without sacrificing analytical power or reliability.
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