Posted by Carl Nestor on January 26, 2018

A common topic when designing an online course revolves around the use of video instruction. The question regularly comes down to “what is the optimal viewing length?” You may hear that Americans have the attention span of a gold fish, or roughly 8 seconds. This factoid, however, is a bit misleading. It’s true that when sifting through a large volume of possible online choices, the mind makes quick decisions, often based on the first ten- seconds of a video. The mind filters the information and almost instantly makes a perceived ranking as to its worth.

But this rule of thumb does not apply in all attention span situations. For example, there is binge watching, or the viewing of numerous episodes of a favorite TV show in a constant stream - for hours. Online gamers can be engrossed online within World of Warcraft game environment. So, this still leaves us with our basic question – what is the optimal length of an instructional video?

For me, this decision isn’t based around a pre-determined number of minutes, but rather culmination of several key factors. You may find that a 15-minute video is more powerful, and memorable, than a 3-minute blip. Getting students to watch videos can be tough. Period. But considering these factors below are a great aid in finding the best length.

The first factor is quality of presentation. Basically, how dynamic is the speaker? First impressions count. If the instructor speaks in a slow, monotone voice or the video begins with two minutes watching the instructor prepare – students will quickly disengaged and shift their attention to checking your phone messages. Ensure your sound quality is good. If the voice recording is not clear or muffled by background noise, you’ll have a tough time keeping viewers watching. Having to strain to understand the speaker quickly becomes tiresome. I’ve found that people are more forgiving of poor image quality than the poor sound.

Another factor is how quickly do you hook the student and draw them into the video. Relevancy is key. In the online article, Attention Span Statistics for video[1], blogger Elishe Lagarde writes “you need to present the viewer with a reason to stay with your video and you need to do it in the first minute of watching time – or less.” Within the first 10 seconds, the viewer is making decisions as to its perceived value in exchange for their time.

A third factor is video length counts. The longer the video, the more chances you have to lose viewers. In the online article, Four ways to keep viewers engaged in an online video[2], blogger Chris Savage stated in a study dealing with an hour-long video that “the average viewer watched 72% of the shorter video and only 50% of the longer video.” A graphic within that article shows that less than 20% of viewers continued to the full hour point.

I’d like to illustrate this factor further by sharing some findings from a recent online course. For our online courses, we embed videos into Blackboard using a software called Kaltura. This software has analytic capabilities that allow us to accurately record student viewing times. The instructor used hour-long video lectures. The online course started with 31 students logging in. But even on the first day of the course, only five students actually watched the whole hour lecture. 11 students didn’t even open the video. By the end of the second week, only 13 students were logging in. Interesting, there was a core group of about 6 students who diligently watched each video in its entirety. Three students watched less than 50 percent and one did not even start the video. This shows that 30 percent of the remaining students watched less than 50 percent of these videos. I share these findings only to encourage everyone to consider the length of their videos. A video not watch is lost opportunity for knowledge.

If you are considering using an hour-long video, try this a simple test to evaluate its optimal length – watch the video yourself. How long do you watch the video before your mind begins to drift? Is there anything that distracts you in the video?

If your video topic is complex and needs time to convey – consider chunking the information into shorter videos. Instead of a one-hour long video, consider making four shorter videos. Have you ever sat in a classroom where the teacher talked for an entire hour straight? Even with an interesting topic, your mind is likely to drift. By chunking, I’m not talking about taking a one-hour video and breaking it into four 15-minute portions; but rather, creating four new shorter videos. Each video would have its own statement purpose and material to cover.

So, what is the optimal video of an instructional video? While the answer is somewhat subjective, from practical experience, I’ve found that 10 to 15 minutes seems to be good length. Consider chunking complex topics into a series of videos. Consider adding activities between the videos to strengthen retention. Use a microphone to get the best sound possible. Consider using slides to keep the viewer’s mind engaged. Keep your viewers watching as long as possible. Your information is valuable.