Someone recently pointed out this research to me. Prof Guo believes, based on the data collected from thousands of educational videos served on EdX, that six minutes is the optimal educational video length. People are willing to watch six minutes, but for every minute longer than that, the average number of minutes drops–drops not just as percentage, but in terms of the total number of minutes. If learners see that a video is 20 minutes long, they’ll quit well before six minutes (perhaps with good intentions of coming back later, but they don’t).
This is interesting for a lot of reasons, but one of them is that the governing body over learning for CPA firms recently gave the OK for firms to give formal credit for nano-learning. But to give credit, nano-learnings have to be at least 10 minutes long. EdX’s data* suggests that’s almost 70% too long!
*Of course, EdX’s data is not specific to adults learning in a professional setting. And naturally there are any number of factors in play that would make a three minute video seem interminable and a fifteen minute or even an hour long video fly by. But it’s still interesting stuff.