Both preparing to teach and teaching positively impact learning outcomes for peer teachers.
We sought to evaluate the independent effects of preparing to teach and teaching on peer teacher learning outcomes. To evaluate the independent contributions of both preparing to teach and teaching to the learning of peer teachers in medical education. In total, 17 third-year medical students prepared to teach second-year students Advanced Cardiac Life Support algorithms and electrocardiogram (ECG) interpretation. Immediately prior to teaching they were randomly allocated to not teach, to teach algorithms, or to teach ECG. Peer teachers were tested on both topics prior to preparation, immediately after teaching and 60 days later. Compared to baseline, peer teachers' mean examination scores (±SD) demonstrated the greatest gains for content areas they prepared for and then taught (43.0% (13.9) vs. 66.3% (8.8), p < 0.001, d = 2.1), with gains persisting to 60 days (45.1% (13.9) vs. 61.8% (13.9), p < 0.01, d = 1.3). For content they prepared to teach but did not teach, less dramatic gains were evident (43.6% (8.3) vs. 54.7% (9.4), p < 0.001, d = 1.3), but did persist for 60 days (42.6% (8.1) vs. 53.2% (14.5), p < 0.05, d = 1.3). Increase in test scores attributable to the act of teaching were greater than those for preparation (23.3% (10.9) vs. 8% (9.6), p < 0.001, d = 1.6), but the difference was not significant 60 days later (16.7% (14.4) vs. 10.2% (16.9), p = 0.4). Our results suggest preparing to teach and actively teaching may have independent positive effects on peer teacher learning outcomes.