Lately there has been an interesting discussion about video in eLearning on the eLearningDev discussion group. Here are my thoughts.
The most effective use of video is as a feedback tool - you record someone performing an action and play it back for them so they can see what they are doing right and wrong. This can be making a presentation, a sports activity (like golf) or any physical skill. Add some coaching and this can be very powerful. This is tough to do on the web but we many not be far from it.
The second most effective use of video is to demonstrate those skills - as in the golf example and in the development of human interaction skills.
The third most effective use of video is for entertainment as on YouTube but there can also be some benefits here for affective learning - video can be useful for changing attitudes.
The least effective use of video is for talking-head lectures - in addition to being very inefficient instruction, it is a poor use of internet bandwidth. Such use of video may be cheap or quick but unless it actually results in some learning, it isn't effective. There are, however, even exceptions to this. In a company, for example, a video presentation by the CEO can be a very powerful way to communicate the importance of an issue. And I believe that there are learners out there who like to think that they are relating to a person and find some connection through a talking head video. It seems to work to get their attention - one of the necessary conditions for learning.
I have long been somewhat amused by the fact that Cisco who is considered a world leader in eLearning has such a heavy reliance on video. I will give them that it is a quick and easy (other than network bandwidth and learning efficiency) way to get information out to people. Sometimes fast is more important than good.
Video segments should be kept short - 10 minutes as an absolute maximum - shorter is better. If you expect a learner to actually perform a task following the video it should be less than two minutes long.
If video is going to be used, it should be done as professionally as possible with good lighting, actors (if any) and scripting. Otherwise it won't be good learning.
If, like any element in the design of instruction, video is used intelligently to help a learner achieve an objective, it can be effective. But it often isn't.