This randomized controlled experiment (N = 707) is the first to examine the role of video, source and user attributes in credibility assessment of online science news videos, and the impact of web-search on this role. We created a science news YouTube video in 12 versions (3 × 2 × 2 for source, quality and popularity). Each participant was randomly assigned to one version and was asked to rate the credibility of the source and the scientific information presented in the video. We found that perceived credibility is positively associated with perceived quality, as well as users' YouTube experience. For those participants who did not conduct an online search during the assessment task, there was a positive association between the presenter's perceived credibility and the video's perceived credibility as well as its popularity; however, such associations were not present for participants who did conduct an online search.
Keywords: discourses of science; media and science; media representations; popularization of science; public understanding of science; representations of science; science and popular culture; science communication; science education.