4.6 Length of audio and video assets
Shorter audio-visual material works better. Longer pieces quickly lose a learner’s attention. Research indicates that the optimum video length in an open online course is two and a half minutes. It certainly isn’t recommended to exceed five minutes.
Therefore if you have plans for including a long video in your course you are advised to break it into a series of short videos, perhaps with text in between videos to introduce each piece and the concepts it explores. You can also use this as an opportunity to raise particular points you want learners to look out for as they watch the video and provide short discussions to read after they have viewed the video. Please refer to Session 2 for examples.