Effect of emotional content on online video sharing among health care professionals and researchers (DIFFUSION): results and lessons learnt from a randomised controlled trial

OBJECTIVES: We assessed the effect of emotional content on the extent to which online videos are shared among health professionals. SETTING: We conducted a two-arm randomised controlled trial. We sent a link to one of two videos by email to participants asking them to watch the video and forward it to their colleagues. PARTICIPANTS: Health professionals and researchers (obstetrics, gynaecology and midwifery) with an email address apart from those in countries where access to YouTube is banned. We estimated that 7000 participants were required. INTERVENTIONS: We compared two online videos providing background information about the WOMAN trial. The videos were the same length and had the same content. However, the intervention video had more emotional impact than the control video. OUTCOME MEASURES: The primary outcome was video sharing and the secondary outcome was views generated by participants. We conducted a χ(2) test for the primary outcome and t-test for the secondary outcome. RESULTS: We randomly allocated 8353 email addresses, 4178 to the intervention video and 4175 to the control. Of these, 221 (5.3%) watched the intervention video and 215 (5.1%) watched the control. In the intervention group, 44 (1.1%) forwarded the video compared with 37 (0.9%) in the control group (risk ratio 1.2 [95% CI 0.8 to 1.8], p=0.44). Mean number of views generated by participants allocated to the intervention video was 0.04 and the control video was 0.03 (mean difference 0.01 [95% CI −0.02 to 0.04], p=0.53). CONCLUSIONS: We found no evidence that emotional content increased forwarding. The trial had low power due to the low video watching rate and the small number of outcome events. A key challenge for online dissemination is ensuring recipients watch the video. TRIAL REGISTRATION NUMBER: NCT02109159; Results.