Win @ Fahmida, Nilar (2025) A psychometric analysis of difficulty index, discrimination index, and distractor efficacy in single best answer questions among final-year medical students in a highstakes examination. In: ICME - IMEC 2025, 9-12 October 2025, Kuala Lumpur.
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Abstract
Objective: The objective of this study was to study the association between DE, DIF, and DI under Classical Test Theory (CTT) as well as evaluate item performance in an undergraduate medical exam. Methods: A psychometric cross-sectional survey was conducted with 60 SBA items administered to 129 final-year MBBS students through census sampling. The inclusion criterion was complete response data. Descriptive statistics (frequency, mean, SD) were used for item-by-item classification according to difficulty and discrimination, and distractor functionality was assessed. Spearman's rank correlation tested correlations between DIF, DI, and DE. Results: Twenty-five (41.6%) were too easy (DIF > 70), 25 (41.6%) acceptable (DIF 30–70), and 10 (16.7%) too difficult (DIF < 30) out of 60 items. Over half of the items (51.7%) were good discriminators (DI > 0.3), while 43.3% were marginal and 5% poor. Distractor efficiency was optimal in the difficult items (80%) and poorest in easy items (41.3%). There was a high positive correlation between DIF and DI (r = 0.327, p = 0.011). There was, however, a highly negative correlation between DIF and DE (r = –0.699, p < 0.001). Between DI and DE, there was no significant correlation (r = –0.144, p = 0.272). Conclusion: Middle-difficulty items best differentiated high- and low-achievers. Easy items had weak distractor functioning, with a quality gap. The negative correlation of DIF and DE highlights the need for improved distractor construction, especially for easy items.
| Item Type: | Proceeding Paper (Other) |
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| Uncontrolled Keywords: | One best answer questions, Difficulty index, Discrimination index, Distractor efficacy, Medical education |
| Subjects: | L Education > L Education (General) R Medicine > R Medicine (General) R Medicine > RG Gynecology and obstetrics R Medicine > RG Gynecology and obstetrics > RG141 Study and teaching |
| Kulliyyahs/Centres/Divisions/Institutes (Can select more than one option. Press CONTROL button): | Kulliyyah of Medicine Kulliyyah of Medicine > Department of Obstetric & Gynecology |
| Depositing User: | Nilar Win |
| Date Deposited: | 08 May 2026 16:18 |
| Last Modified: | 08 May 2026 16:18 |
| Queue Number: | 2026-04-Q3139 |
| URI: | http://irep.iium.edu.my/id/eprint/128529 |
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