Item Discrimination, Difficulty, and Response Time for 4-Option Multiple Choice Questions Versus 3-Option Multiple Choice Questions.

OBJECTIVE

The purpose of this study was to examine differences in item difficulty, discrimination, and response time for multiple-choice exam items with 3 answer options compared with items with 4 answer options.

METHODS

Twenty items were administered on the Biostatistics final exam as a 4-option item from 2017 to 2020 and as a 3-option item from 2021 to 2024. The 3-option items were created by removing the least chosen distractors. Mean item difficulty, discrimination, and response time for each item were collected from aggregate exam performance data provided by Examsoft. Paired t tests were used to compare exam performance metrics between 4-option items and 3-option items.

RESULTS

Item difficulty did not differ between 4-option items (89.75 ± 8.45%) and 3-option items (86.45 ± 15.98%, p =.08). However, item discrimination improved from 0.23 ± 0.11 for 4-option items to 0.29 ± 0.09 for 3-option items (p =.03), whereas response time per multiple choice question (MCQ) decreased from 42.50 ± 14.70 s for 4-option items to 38.10 ± 17.78 s for 3-option items (p =.02).

CONCLUSION

Three-option MCQs may offer advantages over 4-option MCQs in pharmacy education by reducing time spent per exam item and enhancing item discrimination without impacting item difficulty. Educators and scholars in pharmacy should further explore strategies for optimizing assessment efficiency and effectiveness without comprising psychometric quality.