Khan Academy revisited

Khan Academy used to be a good idea. Maybe it still is; I haven’t made anything like a thorough review of their hundreds of offerings, so it’s impossible for me to tell. But I’m skeptical.

Before examining the reasons for my skepticism about asking kids to learn from Khan Academy, let’s take a look at the upside. Originally I felt positive about Khan Academy for three reasons:

  • It would let students learn a topic at their own pace. Pause, rewind, watch something five times…all of these might be useful techniques when learning a difficult topic, and they’re nearly impossible in a conventional classroom.
  • It would give students who miss class (for any reason) the ability to learn what they missed.
  • It would free up class time for in-class interaction with the teacher rather than listening to the teacher lecture.

Those all remain legitimate reasons. But now I believe (from very limited experience) that they are outweighed by four strong reservations:

  • The Khan Academy videos are, by their very nature, almost completely devoid of context. Although there is a certain degree of sequence and order, it’s still impossible for the lecturer to know where the students are in their course. Without context, a course can’t tell a story.
  • Although they don’t have to be, these videos are — to put it bluntly — boring. Teachers aren’t primarily entertainers, but we do have to keep our students’ attention and therefore have to be entertainers from time to time. I haven’t yet seen any Khan Academy videos that hold my interest. Perhaps they do exist.
  • Effective instruction has to involve a lot of practice, interaction, and discussion. Khan Academy is moving toward providing these features, especially the first, but they’re not there yet.
  • It’s inevitable that the presenters cannot be experts in their subject matter and in appropriate pedagogy. The videos cover far too wide a spectrum of topics. Teaching takes a lot of preparation — and new preparation for each course. If I take something I haven’t taught recently (or, worse yet, haven’t taught at all), it’s going to take me dozens of hours of prep to make a short video, and it probably still won’t be very good.

Let’s look at a concrete example. I recently wanted my Algebra II students to a watch a video on using matrices to solve systems of linear equations. This is a fairly complex topic, involving a sequence of many steps. It seemed like a natural for Khan Academy, so the first thing I did was preview their video on the topic. I was treated to 16 minutes of a poorly executed and even more poorly planned presentation on this topic, narrated by Sal Khan himself. If I list all of the flaws, it will bore you even more than it bored me, so let’s just list a few:

  1. The “video” opens with an astounding 53 seconds of blank screen, showing nothing but a wandering cursor accompanied by rambling audio. This is 2012????
  2. Instead of using a prepared example, Khan says, “Let me think of something…uh…3x plus 2y is equal to…uh…let me see…,” and we have dead air while he calculates the rest of the equation in his head, presumably working it out to have reasonable answers. This can be acceptable in a class setting, especially with an audience that has learned to know and trust the teacher’s expertise, but it’s deadly in a video that was prepared in advance.
  3. After constructing the first equation, Khan goes on to say, “and then you might have…I don’t know…minus 6x plus…I don’t know…6y is equal to…[pause]…I have to do this in my head to make sure I get numbers that work out well…” After this painful intro, we go into a several-minutes-long digression about putting the equations into slope-intercept form so we can graph them, all of which is a distraction from the topic at hand. (It’s well-intentioned, but still a distraction.)
  4. Then Khan makes a mistake in graphing. Again, we all do this in class from time to time, but it should be cleaned up in a pre-recorded video (unless the mistake is proving a point, which it isn’t in this case).
  5. We go on and on, and at one point Khan says, “…hopefully I’m not completely boring you….” Sorry, Sal, but you are.
  6. Toward the end, Khan misreads his own handwriting and has to redo part of the solution. Just edit the video!!!

If you don’t believe me, feel free to watch the entire 16 minutes yourself — if you can stand it.

You’ll have to be the judge of whether this video is typical. But let’s go back to my list of pros and cons. If we look at a video on the same subject from a different provider, we can at least separate out the specifics of Khan Academy from the more general idea of using videos for the purpose of learning math. After I rejected this particular video, I searched for an alternative. Go ahead and follow this link, and you’ll see a competent and reasonably lively treatment of the same topic. It’s not flashy (and the last word is glaringly misspelled) but it’s smooth and effective. Letters and numbers are represented in clear type rather than sloppy handwriting. There are no math errors, no false starts, no hesitations. Most importantly, an on-screen TI calculator clearly models for students what they will be doing, and the unknown narrator explains what they’re doing and why. It’s not perfect — and probably I could have found a better one if I had searched long enough — but it’s seven times better than Sal Khan’s.

The moral of the story is that it’s important to separate out the general idea of math videos from the specifics of any provider. More to come…



Categories: Teaching & Learning, Technology