Impact of take-home messages written into slide presentations delivered during lectures on the retention of messages and the residents’ knowledge: a randomized controlled study

Background: Lectures with slide presentations are widely used to teach evidence-based medicine to large groups. Take-home messages (THMs) are poorly identified and recollected by students. We investigated whether an instruction to list THMs in written form on slides would improve the retention thereof by residents, and the residents’ level of knowledge, one month after lectures.Methods Prospective blinded randomized controlled study was conducted. Twelve lectures (6 control and 6 intervention lectures) were delivered to 73 residents. For the intervention lectures, the lecturers were instructed to incorporate clear written THMs into their slide presentations. The outcomes were ability of resident to recollect THMs delivered during a lecture (as assessed by accordance rate between the lecturers’ and residents’ THMs) and knowledge (as assessed by multiple choice questions (MCQs)).Results Data for 3,738 residents’ THMs and 3,410 MCQs were analyzed. The intervention did not significantly increase the number of THMs written on slides (77% (n=20/26), 95% CI 56–91 vs 64% (n=18/28), 95% CI 44–81, p = 0.31) nor THMs retention (13% (n=238/1791), 95% CI 12–15 vs 17% (n=326/1947), 95% 15–18, p = 0.40) nor knowledge (63.8 ±26.2 vs 61.1 ±31.4 /100 points, p = 0.75). In multivariable analyses, superior knowledge was associated with notetaking during lectures (OR 1.88, 95% CI 1.41–2.51) and THMs retention (OR 2.17, 95% CI 1.54–3.04); and THMs retention was associated with written THMs (OR 2.94, 95% CI 2.20–3.93).Conclusions In lectures delivered to residents, a third of the THMs were not in written form, even though the teachers were instructed to incorporate written THMs into their slide presentations. However, there is a strong positive association between writing THMs on a slide, retention of THMs and residents’ knowledge.Trial registration ClinicalTrials.gov NCT01795651 (Fev 21, 2013)