Spaced education improves the retention of clinical knowledge by medical students: a randomised controlled trial.

Purpose: Medical knowledge learned by trainees is often quickly forgotten. How can the educational process be tailored to shift learning into longer-term memory? We investigated whether 'spaced education', consisting of weekly e-mailed case scenarios and clinical questions, could improve the retention of students' learning.

Methods: During the 2004-5 surgery clerkships, 3rd-year students completed a mandatory 1-week clinical rotation in urology and validated web-based teaching programme on 4 core urology topics. Spaced educational e-mails were constructed on all 4 topics based on a validated urology curriculum. Each consisted of a short clinically relevant question or clinical case scenario in multiple-choice question format, followed by the answer, teaching point summary and explanations of the answers. Students were randomised to receive weekly e-mailed case scenarios in only 2 of the 4 urology topics upon completion of their urology rotation. Students completed a validated 28-item test (Cronbach's alpha = 0.76) on all 4 topics prior to and after the rotation and at the end of the academic year.

Results: A total of 95 of 133 students (71%) completed the end-of-year test. There were no significant differences in baseline characteristics between randomised cohorts. Spaced education significantly improved composite end-of-year test scores (P < 0.001, paired t-test). The impact of the spaced educational e-mails was largest for those students who completed their urology education 6-8 and 9-11 months previously (Cohen's effect sizes of 1.01 and 0.73, respectively).

Conclusion: Spaced education consisting of clinical scenarios and questions distributed weekly via e-mail can significantly improve students' retention of medical knowledge.