Recorded lectures on the net are becoming big business. Hundreds of universities now offer free lectures via channels such as iTunes U, YouTube Edu and Academic Earth and many more distribute recorded lectures internally. According to a new survey reported in Campus Technology (College students on streaming video: get me outta class!) about half of the students claimed that they preferred the recorded versions to actually sitting in the classroom. Now admittedly this survey was sponsored by a company that sells videoconferencing equipment but I suspect that the student attitudes are fairly representative.
The advantages of having lectures available online are, according to students in the survey, that they allow you to review them whenever you want, catch up on missed classes, be able to take multiple classes and allow you to fast-forward through the uninteresting parts. They also claimed that recorded lectures helped them prepare better for exams.
The lecture as a teaching method goes back to ancient Greece and is still the staple diet of most university courses. It's amazing that it still thrives despite clear evidence that it doesn't work. Some people learn effectively by listening but most don't and the result is a classroom where many are half asleep or distracted by more engaging activities like Facebook or instant messaging. If teachers take exception to this just look at our own behaviour when we're at conferences; how many are actually listening to the speaker?
Even recorded lectures are seldom particularly stimulating unless delivered by a gifted speaker. I would not claim that we should abolish lectures but we should probably cut them by at least half. In the right context a high quality lecture can inspire and provoke but the message of many mediocre lectures could be better delivered as a podcast or written article. The time saved by not giving lectures can be devoted instead to leading discussion and reflection; a much better use of the teacher's contact time with students.