Are the main points emphasized several times with supporting examples?
Length:
There's a reason TED talks are restricted to under 15 minutes--attention spans for video content are typically no longer than 15 minutes, and are often less. We recommend keeping each video under 10 minutes.
Look for videos that "chunk" topics into shorter, separate videos. The Khan AcademyLinks to an external site. does this very well (click on the link to see this in action). One lesson might be made up of seven different videos with short quizzes interspersed to help reinforce the video content.
Sound & Images:
Does the audio reinforce the information or message of the video?
Is it clear, engaging and even?
This does not mean that is has to be without flaws or produced in a sound studio, but it needs to be clear enough that it is not a distraction
Are images (graphs, charts, photos, drawings, sketches, worked problems) used to reinforce the topic?
It would be hard to demonstrate a math problem without showing the problem. This is an obvious example, but keep it in mind as you evaluate the quality of made videos