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ERIC Number: EJ1358988
Record Type: Journal
Publication Date: 2022
Pages: 15
Abstractor: As Provided
EISSN: EISSN-2148-7456
A Novel Approach for Calculating the Item Discrimination for Likert Type of Scales
Celen, Umit; Aybek, Eren Can
International Journal of Assessment Tools in Education, v9 n3 p772-786 2022
Item analysis is performed by developers as an integral part of the scale development process. Thus, items are excluded from the scale depending on the item analysis prior to the factor analysis. Existing item discrimination indices are calculated based on correlation, yet items with different response patterns are likely to have a similar item discrimination index. This study proposed a new item discrimination index that can be used in Likert type of scales and examined its effect on factor analysis results. For this purpose, simulative datasets were generated, and items were excluded from the analysis according to the 0.20, 0.30 and 0.35 item discrimination index criteria, and exploratory factor analysis was performed for a single factor. Accordingly, it was found that more variance could be explained by a single factor with fewer items compared to other discrimination indices when the 0.20 criterion of the slope coefficient was used as suggested in this study. Similar findings were obtained using the 0.35 criterion with other discrimination indices. In this context, it is recommended to use the slope coefficient as an additional discrimination index calculation method in the scale development process.
International Journal of Assessment Tools in Education. Pamukkale University, Faculty of Education, Kinikli Campus, Denizli 20070, Turkey. e-mail:; Web site:
Publication Type: Journal Articles; Reports - Research
Education Level: N/A
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A
Grant or Contract Numbers: N/A