Added Value of Subscores for Tests With Polytomous Items.
Kylie Gorney1, Sandip Sinharay2
1Michigan State University, East Lansing, MI, USA.
Educational and Psychological Measurement
|November 20, 2024
Summary
Subscores offer valuable feedback in educational testing. This study finds that subscores are more likely to provide added value in tests with polytomous items compared to dichotomous items.
Area of Science:
- Educational Measurement
- Psychometrics
Background:
- Growing demand for detailed performance feedback from testing programs.
- Interest in using subscores to provide more granular insights.
- Classical test theory (CTT) provides a framework for evaluating subscore added value.
Purpose of the Study:
- To investigate the added value of subscores in educational testing.
- To determine if subscores provide meaningful information beyond the total score.
- To compare the added value of subscores in tests with dichotomous versus polytomous items.
Main Methods:
- Utilized Haberman's classical test theory-based method for assessing subscore added value.
- Analyzed data from tests featuring polytomous items.
- Compared findings with previous research predominantly focused on dichotomous items.
Main Results:
- Subscores are more frequently found to have added value in tests with polytomous items.
- This contrasts with previous findings where subscores rarely had added value, often due to a focus on dichotomous items.
- The nature of item format significantly influences the added value of subscores.
Conclusions:
- Subscores can provide significant added value, particularly in assessments with polytomous items.
- The reporting of subscores is more justified when items are polytomous.
- Future research should consider item format when evaluating subscore utility.
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