Khan Academy view of mastery learning

The terms mastery learning are used a lot these days, but I want to do a video on them because they can mean different things to different people. I want to talk about what it means, at least in a Khan Academy context.

So to give us some perspective, let's actually start with traditional learning and think about where it works and maybe where it doesn't work. Then we could think about why mastery learning might address some of those issues.

So let's say we are in a middle school math class, and right now the classroom is focused on negative numbers. We have, we're going to work on that for a couple of weeks. So this is negative numbers right over here. After a couple of weeks of lecture and homework, we give a test. Let's say a certain student that we're following gets an eighty percent on that test.

So he or she knows a lot of the material but doesn't know some of the material here. Maybe doesn't know some of the material here, maybe doesn't know some of the material over here. So these are gaps; these are gaps in their understanding. So let me label these correctly: these are gaps.

Even though we've taken the trouble of giving an assessment, a quiz, a test, and we identify these gaps, the whole class, including that student, will then move on to the next concept. So let's say the next concept that we now work on, maybe we do it for a few more weeks according to the lesson plan, is now basic exponents.

So this is basic exponents, and the same thing happens. We have some lecture and homework for a few weeks, and then at the end of that, we have a test. Let's say on that test the student gets a 70. So he or she knows a good bit of the material, but there's still some pretty significant gaps.

Let me color in these gaps. So the white is what they were actually able to perform on these tests, and even these tests are imperfect; they're just sampling the student's knowledge. So what happened to be on the test, they still didn't know some of the material. Some of it might have been careless mistakes, but some of it might have been pretty important.

For example, this gap right over here might be what happens if I raise something to the zero power. Or maybe it's building on top of a gap with negative numbers. Maybe this gap is happening not just because basic exponents are difficult but because there's a gap in negative numbers.

So the student doesn't know, well, what does it mean if I take a negative number to a positive exponent? So maybe that's a gap there. But even though we've taken the trouble of identifying those gaps, the class will then move on to the next concept. The amount of time is what's fixed, and what's variable is how well the students understand it: A, B, C, D, or F.

Then the next concept, let's say, let me do this in another color. So the next concept here we are building on top of everything that we've learned so far. Let's say it is negative exponents. So I think you can see where this is going. This is trouble now for the student. There is lecture and homework; the student is trying the best they can, but things are just not really gelling.

And so all of a sudden when you take the quiz, the student just hits a wall. After two or three weeks, let's say they get a thirty percent, and so they're only able to get thirty percent of the material right that happened to be on the test; the rest they got wrong.

Now, in a traditional system, we say, all right, the student just failed this exam quite badly. Maybe the student needs to work harder. Maybe they need to be put into a different track. Maybe this subject is just too difficult for this student.

But when you look at what's going on, it's pretty clear that it had nothing to do with the ability level of the student, and it didn't have anything to do with the difficulty necessarily of the subject matter. But it's more that they just kept accumulating these gaps all along the way. So at some point, those gaps become so debilitating that the student hits a wall and starts failing a class.

And if they're not able to remediate these gaps, go back, well, they're never going to really be able to understand negative exponents, and then they're never going to be able to understand logarithms properly, and more advanced algebra, and so on and so forth.

And we've all seen this, either for ourselves or some of our friends and family members. They hit walls. The argument that we believe at Khan Academy is that it is not because they're not bright; it's not because the subject matter is difficult. It's because we're forcing them through at a fixed pace.

And to realize how absurd this is on some level, imagine if we did other things in our life that way. Say home building. So you tell the contractor, "We have two weeks to build this foundation. Do what you can." And so they build a foundation, but then two weeks later the inspector comes and says, "Okay, the concrete's still wet right over here. This part isn't quite up to code. I will give this an 80 percent."

And you say, "Great, that's a C. Let's build the first floor." And so again, you try to build the first floor. Maybe it rains; some of the supplies don't show up. And so the inspector comes after a couple of weeks and says, "All right, I'll give that a 70." And you say, "Great, that's a D. Now let's build the second floor," and so on and so forth.

And then all of a sudden while you're building that second floor, the whole structure comes collapsing down. And if our reaction to that is the reaction we typically have in education, we say, "Oh, we needed more inspection," or "we needed better contractors." But the problem was the process.

We are artificially constraining how long you have to do something, which pretty much ensures a variable outcome. You take the trouble of identifying those gaps but then you build right on top of it. So this is traditional learning, and one could argue that if you're just pushing people ahead at some pace like this, gaps will accumulate for everyone, and they will all hit a wall at some point.

We've all felt that. Mastery learning says, look, instead of making everyone go at the same pace, let us personalize. And personalization, in this context, means let people go at their own pace. So traditional learning has a fixed pace, fixed pace, and variable understanding, variable, variable understanding.

While mastery learning has personalization, so it's more of a variable pace, variable pace, and then we assume students get to a high level of proficiency or mastery, so high expectations around proficiency or mastery. And those words can mean different things in different contexts, proficiency or mastery.

In a mastery learning system, maybe the student would be ready for the negative numbers, and maybe after a few weeks, they take some type of an assessment to get as much practice and feedback as possible. They perform similarly to that first example: the student in the first example, maybe they get that 80 percent.

There, in a mastery learning system, we wouldn't just tell that student, "All right, let's move on to basic exponents." What we would do is, "Hey, why don't you keep working on the negative numbers here," so that you can address those gaps.

So it might take a student a little bit more time, but eventually, they're able to fill in those gaps. They might still be a few small gaps, but the whole point is that they can always go back and revisit and ensure that they fill in those gaps so that they don't become debilitating.

Ideally, they fill in all the gaps, and now they're ready for basic exponents. I’d argue that now that you're tackling basic exponents, the student actually might be able to even learn it faster because they're going to get less confused by the negative exponents.

But if they still end up having a gap when they take some type of an assessment or while they're doing practice, they have as much time as they need to go back and fill in those gaps. So the whole principle here is that in mastery learning, the student is building a really solid foundation so that they never hit that wall.

When they get to negative exponents, they understand their negative numbers well; they understand their exponents well. And so then they can just keep on going and going and going. At Khan Academy, we believe that if you learn this way, yes certain subjects might take you a little bit longer, but then if you invest there, the future subjects will take less time, and you will understand more overall.

And we've seen efficacy studies to this effect; you will actually learn better, faster, and you won't eventually hit some type of a barrier like the first student did with negative exponents.