The Art of the Chunk

Filed in Announcements by on July 31, 2018

When recording an educational video, we know how to click the record button. But how do we know when to click stop? WPI’s instructional designer Caitlin Keller is here to offer guidance on when enough content is enough.

“As the average person can only hold 4 – 7 bits of knowledge in working memory at a given time, it is important to break new material down into chunks that are digestible,” she says.

Beth Wilson, Adjunct Teaching Professor for WPI’s Corporate and Professional Education, adheres to Keller’s advice. Wilson purposely makes her videos chunky by keeping them to less than 10 minutes.

“I have to really convince myself that the material can’t be condensed or partitioned to run over,” Wilson says.

Wilson, who teaches Computer Science and Systems Engineering, creates an average of 4 videos per module for each course. “I could read an hour course overview, but I think the sections help the students digest the pieces better,” she says.

Keller agrees. “The act of chunking video is a great step in helping students stay focused on specific content,” she says.

Brent French, Professor of Organizational Science at The Business School, says that for him, 20 minutes is a “sweet spot.”

“Over the past six years I’ve taught (about) 35 sections of graduate students with professional experience, and 20 minutes of presentation seems to coincide with what they are used to in a workplace setting.  For undergraduates who are accustomed to longer lectures, 20 minutes might be too short, but for working professionals 20 minutes fits.”

One trick that helps keep videos to a digestible duration is writing a script. In her Online Faculty Institute, Keller advocates for script writing as a part of pre-production planning for curricular content that is delivered via video.

Wilson, a former student of Keller’s, found this technique particularly helpful. Wilson was initially interested in this technique as a way to make her videos hearing accessible. Students could download the script if they could not listen to the audio.

But in addition to accessibility, Wilson found that creating a script helped her stay on track. “When I write a script, I am less likely to detour on a story that is fascinating but irrelevant,” she states.

In 2014, researchers at MIT analyzed data from 2.5 million EdX video viewing sessions. The analysis showed that students were the most engaged with videos of 2.5 minutes in duration. At WPI, educational videos range from about two minutes to three hours, with the instructional design and technology team encouraging the shorter end of the range.

But length is not the ultimate determinant of a video’s efficacy.

“I judge the quality of my videos by how well the students do on the related assessment,” writes Wilson. French echoes that thought. “If they watch videos it’s apparent in their work on papers and exams,” he states.

For information on how to create and share educational videos at WPI, feel free to contact the Academic Technology Center’s Technology for Teaching and Learning Group at

About the Author ()

Sophie Jagannathan is an Instructional Technology Specialist at Worcester Polytechnic Institute.

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