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Current time:0:00Total duration:8:42

Video transcript

- [Instructor] The terms mastery learning are used a lot these days but I wanna do a video on 'em because they can mean different things to different people and I wanna just talk about what it means at least in a Khan Academy context. So to give us some perspective, let's actually just start with traditional learning and think about where it works and maybe where it doesn't work and 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're gonna work on that for a couple of weeks. So this is negative numbers right over here and after a couple of weeks of lecture and homework, we give a task and lets say a certain student that we're following gets an 80% 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 these, we label these correctly, these are gaps. And even though we've taken the trouble of giving an assessment, a quiz a test, and we identified 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 and let's say on the 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 students' knowledge and so what happen to be on the test they still didn't know some of the material. Some of it might've been careless mistakes but some of it might've 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 was happening, not just 'cause basic exponents are difficult but because there's a gap in negative numbers so the student doesn't know 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. And then the next concept, let's say we'll 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's 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 and let's say they get a 30% and so they're only able to get 30% of the material right that happened to be on the test, the rest they got wrong. Now, in a traditional system, we say "alright, 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 the 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 the 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. And the argument that we believe at Khan Academy 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%" 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, "Alright, I'll give that 70%" and you say "Great, that's a D "Now let's build the second floor" so on and so forth 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 and we've all felt that. And so 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, it's fixed pace and variable understanding, while mastery learning has personalization. So it's more of a 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 context, proficiency or mastery. So in a mastery learning system, you first would maybe the student would be ready for the negative numbers and maybe after a few weeks, they take some type of assessment, to get much as much practice and feedback as possible and they perform similarly to that first example, the student in the first example, maybe they get that 80% there. In a mastery learning system, we wouldn't just tell that student, "Alright, let's move on to basic exponents" what we would do is, hey, why don't you keep working on the negative numbers here and so that you can address those gaps. And so it takes the student maybe a little bit more time but eventually, they're able to fill in those gaps. There might be still 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'll fill in all the gaps. And now, they're ready for basic exponents and I'd argue that now that you're tackling basic exponents, one, the student actually might be able to even learn it faster 'cause they're gonna 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 and so the whole principle here is in mastery learning, the student is building a really, 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 and 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 and overall and we've seen efficacy studies to this effect, you'll actually learn better, faster and you won't eventually hit some type of a barrier like the first student did with negative exponents.