Brief problem‐solving questions in medical school examinations: is it necessary for students to explain their answers?

Objective To compare outcomes when answers to objective type problem-solving questions are marked with and without consideration of students’ explanations of their answers. Design Students answered six multiple-part problem-solving questions on the final examination for a course in clinical biochemistry. Each part required a choice from a list, a number or a few words, plus an explanation or justification. Scores were determined independently for the answers alone and for the answers plus explanations. The outcomes of the two marking methods were compared. Setting Department of Pathology, University of Otago Medical School, Dunedin, New Zealand. Subjects Final year preclinical medical students. Results Marks were slightly higher for answers alone than for answers plus explanations (overall mean, 82·1%; standard deviation, 9·8% vs. 77·1%; 9·3%; P < 0·001 by paired t-test). There was a very high correlation between scores derived from the two methods (r=0·87). Consideration of the answers alone (without explanations) was about as good as answers plus explanations in identifying students who performed at different levels overall on the examination and in identifying the weakest students. Conclusions The data suggest that when students arrived at the correct answers, their information and reasons were usually correct and that answers alone discriminate adequately among students with different levels of knowledge and ability. By dispensing with the requirement for explanations, we would be able to ask more questions and mark objectively, so competent students should not be disadvantaged by the lack of opportunity to explain their reasoning.