Student engagement in a flipped undergraduate medical classroom to measure optimal video-based lecture length

Purpose: to determine the optimal length of video-based lectures for undergraduate medical students in a flipped classroom environment, considering not only audience retention (AR) but also other complementary aspects. Methods: a total of 173 videos were used across three consecutive courses. The outcome variables included the percentage of video viewing, viewing index, AR percentage, early dropout percentage, percentage of students who did not access the clip, and percentage of students answering the questions embedded in the clips. Information was obtained from the own platform at the end of each course. All the outcome variables were considered a function of the video length over or under different cut-off points.