Psychometric Evaluation of Forensic Medicine Multiple-Choice Questions: An Item Analysis From a Nepali Medical College.

Abstract

Background: Multiple-choice questions (MCQs) are test items that are essential to assess the competency of medical students in forensic medicine. However, the psychometric quality of these test items in Nepali medical colleges remains largely unexplored. This study evaluated the difficulty index, discrimination index, and distractor effectiveness of forensic medicine MCQs to identify areas requiring improvement.

Methods: This cross-sectional study evaluated 30 MCQs from the end-of-semester forensic medicine examination which was administered to 100 third-year medical students. The item difficulty, the discrimination index (via Kelley's 27% method), and performance of the distractor were calculated for each question.

Results: The students showed high performance, with a mean score of 23.25±3.61 out of 30. Difficulty analysis showed that majority of the items (60%) fell within an acceptable difficulty range (70-90% correct), while 16.7% were very easy and 6.6% were difficult. Discrimination was good in 43.3% of the items, moderate in 23.3%, and poor in 33.3%. Distractor analysis identified non-functional distractors in a large proportion of items, including nine items (30%) with at least one zero-response option. Overall, 44 of 90 distractors (48.9%) across all items were non-functional. A statistically significant negative correlation was found between item difficulty and discrimination index (ρ = -0.4265, p = 0.019); items of moderate difficulty (50-69% correct) showed the highest mean discrimination, with both moderate- and acceptable-difficulty items outperforming items at the extremes of difficulty.

Conclusions: The examination revealed adequate student performance; however, item quality analysis demonstrated the need for improvement, with approximately one-third of the items failing to meet the desired standard and therefore requiring revision due to poor discrimination or non-functional distractors. Structured faculty training in item-writing principles and regular psychometric evaluation may help improve assessment quality in Nepali medical education.