Saturday, September 28, 2013

Teaching to Mastery

I was listening to Salman Khan, founder of the Khan Academy, on the radio this morning and was particularly struck by one point he made - the notion of replacing grades with teaching to mastery. It's a concept I had been interested in for a while, but it seems to me that computer aided instruction is what makes it really possible. It's not news to students in Science, Technology, Engineering, and Mathematics (STEM) subjects that you learn more from doing the problems than listening to lectures. As a culture, though, we are so wedded to the notion creating a hierarchy (A,B,C,D,F) that we are far more likely to regard problem sets and exams as filters rather than as teaching tools.

One severe constraint on education has always been the amount of time it takes to administer, evaluate, and score exams and quizzes. That fact traditionally forced schools to allocate time in such a fashion that while a few students would have thoroughly mastered the material by the time it was time to move on a new subject, most would have only a partial grasp of the material and others would not get it at all. In subjects like math this is particularly destructive, since each level of math tends to build on preious lerarning, so being a little behind in addition leads to being quite a bit behind in multiplication and utterly at sea in fractions, for example.

The Khan Academy gets beyond that with technology, by having repeatable lessions stored on line and continuous testing of a concept until mastery is achieved. Grades are replaced by certifications of mastery that are arguably of more pertainancy. Knowing that a student got an A in elementary algebra (or quantum field theory, or whatever) really only tells us that she was a little better at it than some other set of students that she took the class with. Knowing that they have mastered a specific set of techniques is probably far more significant as a diagnostic. It's the kind of standard that the best have always demanded of themselves. Abraham Lincoln, for example, worked at Geometry until he could prove all the propositions of Euclid's first six books at sight.

The quizzes and exams of Coursera and edX permit the instructor to select how many times the quizz can be taken, and some instructors have taken to making those numbers large 100 or even 500 times. Of course that means that every persistent student can get a perfect score, which to me is an excellent idea. It would probably be better still if detailed track were kept of what kinds of problems students had trouble with, so that extra examples of that type could be given - something the Khan Academe already does.

That approach means taking a decisive step away from college as a tournament and toward college as an education to mastery. Grades would be replaced by badges of mastery. The tournament would hardly be abolished however, since the number and kinds of badges achieved would still vary.