Donald Clark Plan B: Video for learning –15 things the research says – some may shock you…
Summary of research on using videos for learning. Video length, using "talking heads," cuts, screen size, and more.
Optimal Video Length for Student Engagement | edX
In edX courses, about 6 minutes is the maximum length students will watch. In traditional online graduate courses for credit, the length could be longer, but this is a good reminder to keep things short.
The optimal video length is 6 minutes or shorter -- students watched most of the way through these short videos. In fact, the average engagement time of any video maxes out at 6 minutes, regardless of its length. And engagement times decrease as videos lengthen: For instance, on average students spent around 3 minutes on videos that are longer than 12 minutes, which means that they engaged with less than a quarter of the content.