Public engagement with clinical research on social media; which visual medium works best? A 5-year retrospective analysis

'Public engagement' describes a collaborative relationship between scientists and the public we serve. This has the potential to improve clinical research and is encouraged by key research funding bodies, however the objective evidence base for effective approaches remains limited. Social media algorithms determine what content users see and are known to weight post media differently. While visual content is understood to improve reach and engagement broadly, less is known about which kinds of visuals are most effective for engaging people with clinical research. We present a five year retrospective analysis of public engagement with Facebook posts made by an independent medical research institute, classified by their visual media content. Inclusion of visual post media was associated with positive effects on both reach and engagement. We present medium and strong evidence that this effect was most pronounced for comics compared to other visual media types. This data evidences objective value of using comics and other visual media for public engagement with clinical research. The metrics evaluated are easily accessible on many social media platforms meaning this approach could readily be applied by other researchers to measure the impact of their public engagement efforts, and inform science communication strategies and resource allocation.