PURPOSE
Differential Item Functioning (DIF) occurs when medical students from
different demographic groups (e.g., sex, ethnicity) have unequal
probabilities of answering a test question correctly, despite equivalent
ability. The purpose of this study was to explore whether medical students
could recognize causes of DIF and provide insight into sources of bias in
assessment items.
METHODS
Final examination items from a second-year course were analyzed for DIF.
DIF was analyzed using standard logistic regression methods based on sex,
race, ethnicity, and native language proficiency for each item. Focus groups
using the Nominal Group Technique were conducted with UCF COM medical
students (M1-M4). Groups of 4-6 students reviewed six items with the largest
computed DIF, discussed observed patterns, and provided feedback on improving
test fairness.
RESULTS
Students consistently identified clarity and formatting issues such as
run-on sentences, missing punctuation, and dense lab data, as barriers to
comprehension. They emphasized the importance of clinical authenticity,
noting that incomplete lab values and inconsistent units could weaken
validity and clinical reasoning. Concerns about curriculum alignment arose
when items included unfamiliar terms not emphasized in lecture, raising
equity issues since students rely partly on third-party resources. In
addition, students identified a logical basis for DIF in a minority of cases,
often linked to contextual features that might inadvertently advantage
certain racial or socioeconomic groups.
CONCLUSION
Students highlighted clarity, formatting, clinical authenticity, and
vocabulary as sources of bias in medical school assessments. Addressing these
issues can reduce construct irrelevant variance, strengthen validity, and
promote equity. Incorporating student perspectives into item review can help
provide faculty with actionable strategies to improve test design and ensure
fairness in high stakes examinations.