[yummyfajitas]

I'm focusing on cost because I don't see how a video lecture can be dramatically better than an in person one, but I can easily see how it could be just as good. This could be a failure of imagination on my part.

A model I'd like to see attempted - 2 hours of lecture (video) + 1 hour of recitation (human supervised), in lieu of 3 hours of lecture+recitation by a human. Now a single human can teach 3x more classes. That's a massive reduction in costs, but I don't see how it can significantly increase educational outcomes.

There is one caveat - I expect lecture quality would improve a bit. If only the best teachers record videos, then lecture quality will be better than average. By definition, human-delivered lectures can only be average.

[whatusername]

For me the killer thing about Khan's lectures is how broken down into small chunks that they are. If you don't get it -- you can watch the 10m lecture again. Not to mention you can pause/rewind, there are theoretically no distractions (like disruptive members of class), and then the point you made about lecture quality.

I really like Khan's model of doing lectures/learning at home -- and using the classroom time for exercises // with the teacher (or other students) mentoring those who are stuck on a problem set.

[kenjackson]

Lecture quality improves, and students can also learn at their own rate. You should read some of the feedback on Khan lectures. Students can pause, and look up other sources. And they can daydream, but still not miss any material.

It's unclear to me that even a 1/3 reduction in lecture time is sufficient. I'd like to fundamentally change education so the teachers are really mentors and facilitators of learning and activities. Lecturing can be done via video almost exclusively -- at least for those topics where video lectures make sense.

[joebadmo]

Exactly. That's sort of what I (and I think KA) was getting at.