The Dangerous Mr. Khan

I would assume that studies comparing a competent physics teacher to a video instructor would show the former being more effective.

However, there is a shortage of competent physics instructors. There is a (possibly bigger) shortage of competent maths teachers. I am speaking from my more extreme experience in South Africa, where most of the teachers are abysmal. Expensive video-based instruction helped me achieve a respectable mark in physics/chemistry, most of my peers lacked that privilege and did very poorly. Even at university, things like differential equations, linear algebra and calculus were not particularly well taught - most professors are not really good at teaching, and in my case, they were teaching in a second language (Afrikaans speakers teaching English speaking students). The Khan Academy would have helped me even at the undergraduate level.

I have posted to HN in a related thread about video instruction in South Africa [ http://news.ycombinator.com/item?id=2351100 ]. People have been doing it for years here. I would recommend a controlled study in South Africa using KA, or The Learning Channel videos by William Smith (NOT run in an elite private school, but at an average township school) before we write off video based instruction as "ineffective".

IMO, it'll be good if KA focuses on the hard basics like mathematics. (By "hard" I don't mean "difficult" btw.)

We created ShowMeApp.com exactly for this reason - so that any teacher can easily create these kinds of videos through the iPad and share them online.

Here's a guy who's done a ton of awesome Chemistry lessons: http://www.showmeapp.com/jr_orinion

We're huge fans what Sal is doing and would love to see more teachers embrace his approach.

We're still in beta, but I'd love to hear any feedback on the site and the app.

One item in particular that hasn't been much discussed here is the self-paced exercises. In here, students can try a problem, to see if they understand the content; and they keep trying until they get 10 in a row. The Khan Academy logs data about how many tries and how long it takes, so they have data on what they consider to be "mastery" (this may be an oversimplification...) There is also a certain game-play aspect which I think is kinda cool, and I like the map of linked concepts/exercise sets. As far as I see, they only have math problems up there as of now.

At face value, it looks like plug-and-chug, drill-and-kill methodology that irks any teacher of merit. But: there are opportunities to take this infrastructure and make it so much stronger ("formative" vs "summative").

Diagnoser.com is an example of an online exercise bank that includes aspects of several decades of physics education research (also some chem and life science) but the concept could be generalized for other disciplines as well. Each question includes "distractors" (wrong answers) that appeal to certain common misconceptions (what they call "facets" of understanding). If you get it right, great! you go on to another problem that might pose a similar question with a twist to challenge you. If you get it wrong, it recognizes from your answer what your misconception might be, gives you a quick mini-lesson to challenge your thinking on that, and gives you a related (though not the same) problem to see if you get it (for physics teachers: like an interactive FCI). The data is reported to the teacher, including right/wrong answers, and the "facets" that correspond to certain ideas and misconceptions. The teacher can see where their teaching (or in this case, Khan videos) have been effective, and where they could use more work (perhaps suggesting the student watch or review a particular video). NOTE: this is only one aspect of the Diagnoser Project's larger program, so I have taken it out of context, but it seems appropriate for this discussion.

This formative approach is effective especially for the conceptual problems, not just the plug-and-chug problems that I saw on the KhanAcademy.org site. Yes, this is much more difficult to program than "right/wrong, next!" problems, and requires research to write good facet-based "distractors" (take advantage of years or decades of education research out there!) but it (a) gets more useful data than just "right/wrong" and (b) allows students to act on their wrong answers immediately by challenging them to think about why it was wrong. I think incorporating something like this with Khan's gameplay/scoring/data collection methods would make the exercise feature much stronger.