# The Case for Teaching for Mastery

Sal Khan is the founder of the online Khan Academy which provides free instruction in mathematics, science, and computer programming. In his November 2015 TED Talk, Khan suggested a vision for education that would operate similarly to martial arts instruction. He explains that:

In a martial art, you would practice the white belt skills as long as necessary, and only when you’ve mastered it you would move on to become a yellow belt.

He described this approach as a mastery model that lets students learn at their own pace.

Currently, the traditional academic model groups students together by age and moves them all at the same pace through the material. Khan uses the example of teaching exponents. The teacher goes over the basics of exponents and gives students homework. Later, the teacher gives a test. On this test, even if the student does okay from a grading perspective with a grade of, say, 75%, that still might indicate that the student hasn’t mastered 25% of the material and yet that student will be forced to go on to the next topic. Khan notes that this process will continue like this until eventually, whether in algebra class or trigonometry, the student will hit a wall. He explains that this is “not because algebra is fundamentally difficult or because the student isn’t bright” but rather is because the 25% of material on exponents that the student never had a chance to master is showing up and the student doesn’t know how to proceed in learning this new topic…

Khan notes the ludicrousy of our current system. He asks us to imagine building a house in this manner. The builder says to the contractor, “we only have 80% of the foundation laid down” and the contractor responds “that’s okay, here’s a C grade and we’ll just build on top of this incomplete foundation.” If we wouldn’t assemble a house this way, why would we assemble a student’s education this way?

The mastery approach lets students spend the time they need to build strong foundations so that by the time they get to calculus or organic chemistry or whatever other field of study, they are equipped to learn complex topics. Khan says that:

It’s important to realize that not only will this make the student learn their exponents better, but it’ll reinforce the right mindset muscles. It makes them realize that if you got 20 percent wrong on something, it doesn’t mean that you have a C branded in your DNA somehow. It means that you should just keep working on it. You should have grit; you should have perseverance; you should take agency over your learning.

As a hypothetical example, Khan asks us to imagine that we had the best possible education system: in such a system, what percentage of students might master calculus and organic chemistry. We might be tempted to say a low percentage like 30% but that’s likely just because in our experience, less than a third of our classmates were ever good at those subjects. But Khan guesses that if we were allowed to use a mastery framework, that number might actually be a lot closer to 100%.

Andrew“…Khan guesses that if we were allowed to use a mastery framework, that number [proportion of students reaching mastery in difficult subjects] might actually be a lot closer to 100%.”

What data supports his guess? My 20+ years’ experience in high school math suggests that human intellectual ability is distributed normally, and that the law of diminishing returns would quickly take over. While mastery learning may work well with elementary (K-8) level academic concepts, there are some students who will likely never master higher math, organic chemistry, or quantum physics. Just as we tell our kids that most of them will not make it to the NBA, we must be realistic with academic achievement also. I understand the desire to get the most from all of our students, but let’s not cut back on the range of material for our highest achievers by spending too long on every topic. Of course balance is the key here.

AnonymousI like the approach of mastery learning but jumping to a conclusion that 100% of students can (or implicitly should) learn college material is a conclusion coming out of nowhere. Really, Kahn is conflating two concepts.