The Cult of Pedagogy Podcast, Episode 116 Transcript
Jennifer Gonzalez, Host

We live in a time when a person can learn just about anything from YouTube. And when it comes to creating free instructional videos, Khan Academy has been leading the pack for the last decade, starting first with math videos, then branching out to include tutorials on science, computer programming, history, economics, and even grammar.

Recently, Khan Academy has added a new layer to its platform that could really be a game-changer for all of us: mastery learning. This system allows students to go beyond cherry-picking videos and instead take full courses, measuring their progress as they go, earning mastery points, reaching new skill levels, and completing challenges. Teachers whose students use the platform have a dashboard that shows student progress.

It’s important to note here that digital learning programs are not a substitute for many of the experiences students should be having in our classrooms. A rich, robust, empowering education gives students regular opportunities to talk with each other, actively problem-solve with real-world tasks, collaborate on multifaceted projects, impact their communities, and wrestle with life’s big questions. These need to be designed and facilitated by live human beings who build relationships with students.

With that being said, platforms like Khan Academy can effectively take over some of our instructional tasks—like differentiating lessons based on student readiness, assessing individual skills, and assigning tasks to fill gaps—so that we can focus our time on planning and implementing those activities that build relationships and engage students at higher levels.

In this episode I’m talking to Khan Academy’s founder, Sal Khan, about how the platform has evolved over the years, how their mastery learning program works, why they built it, and how teachers and students can get started.

Support for this episode comes from Pear Deck, the tool that helps you supercharge student engagement. With Pear Deck, you can take any Google Slides presentation, add interactive questions or embed websites, and send it to student devices so they can participate in real time while you present. And now Pear Deck has teamed up with Google on Be Internet Awesome, a free digital citizenship curriculum that helps kids learn to be safe, more confident explorers online. Pear Deck educators worked with Google to create interactive presentations that accompany the lessons from Be Internet Awesome. Each one gives teachers a simple way to introduce a concept related to digital literacy. And because they’re editable, they’re easy to tailor to your students’ grade level. The basic version of Pear Deck is free, but my listeners can now get a complimentary 60-day trial of Pear Deck Premium with no credit card required. This will give you access to features like the teacher dashboard, personalized takeaways, and more. To learn more, head to

Support also comes from NewseumED. Are your students able to tell real news from fake? Can they recognize bias in sources and in themselves? Are they savvy searchers? Today’s media landscape can be tricky and NewseumED, a FREE educational website, has the tools and tips to help students tackle the challenges. Their newest suite of resources—called Fact Finder: Your Foolproof Guide to Media Literacy—has 11 flexible, multimedia lesson plans to prepare students to identify the type of information they’ve encountered; understand why they’ve found it; and evaluate its purpose and credibility. To learn more and to receive a special offer, visit

The Cult of Pedagogy Podcast is part of the Education Podcast Network. The EPN family now includes 27 different podcasts, and each one is focused on education. Check out all of the EPN podcasts at

One last thing before we get started: I want to thank you for the reviews you’ve left for this podcast on iTunes. Every positive review brings more educators to this show, so if you think I’m sharing things that teachers need to hear, leaving an iTunes review is a great way to get the word out. Thanks so much.

Now here’s my interview with Sal Khan.

GONZALEZ: Sal Khan, welcome to the podcast.

KHAN: Thanks for having me.

GONZALEZ: So we’re here to talk about some new features on Khan Academy, but what I would love to do before we get into that is just for any listeners that are not familiar with Khan Academy, which seems impossible to me, but let’s get all on the same page. Give us a brief overview of what your platform has traditionally offered, how you started, and what people typically think of when they hear “Khan Academy.”

KHAN: Sure. Khan Academy, we’re a not-for-profit organization with a mission of providing a free world-class education for anyone anywhere. There’s really two pieces of that. One is an access piece where we think anyone on the planet who wants to tap into potential should be able to, and so that’s why today we have over 70 million registered users who are accessing us from around the world on anything from early learning through college-level humanities and science and mathematics. When you go to Khan Academy, a lot of people associate us with videos that I started making for family members almost, actually over 10 years ago. And that’s still part of Khan Academy, but really the heart of Khan Academy is our core practice platform where students can learn at their own time and pace, get as much practice and feedback as they need, teachers get dashboards to understand where students are and to be able to intervene accordingly. As I just kind of touched on it, it started in a fairly surprising way back, actually a while ago now, in 2004 I started tutoring family members. Word gets around to my family that free tutoring is going on, so it started to become a lot of family members. I actually started writing software so that they could practice, really fill in their gaps. And that was the first Khan Academy. It had nothing to do with videos. And it was only later that a friend suggested that I make videos to supplement the practice. And I initially thought it was a horrible idea, I thought YouTube’s for cats playing piano, not serious mathematics. But I got over the idea that it wasn’t my idea, and I gave it a shot. It really helped my cousins, and it soon became clear that it was helping people who weren’t my cousins.


KHAN: Yeah. And that was the start. In 2010, or 2009, I quit my day job. My original background is in math and in computer science, but at the time I was working as an investment analyst, and I quit that day job because I just felt like hey, this Khan Academy thing, maybe one day, and I was operating out of a walk-in closet at the time, so it was a little bit delusional, but maybe we can create an institution that could really empower a lot of learners and teachers around the planet.

GONZALEZ: Right, right. And now it’s massive and it’s way more than just math anymore. You cover, how many different topics on the site?

KHAN: You know, it depends on how you account for it, but I think there’s over 30 different subject areas. There’s many thousands of videos just in English. We have tens of thousands of practice items. You know, it’s really functionally infinite. It’s much more than me now, I have to be very clear.


KHAN: Khan Academy is still, people often index on how it got started, but we have a team of teachers, learning experts, software engineers, designers here just trying to do our best to make a dent.

GONZALEZ: And the whole site is free for users, correct?

KHAN: Yeah. I mean that’s, it’s in our mission statement, and that’s always, you know, in the early days of Khan Academy back in 2007, 2008, I live out here in Silicon Valley, and I had people coming up to me and saying, hey, we’ll fund this. You should do this as a venture-backed for-profit company. You could keep certain things free, but then certain things you could charge for, and that just didn’t feel right. I had letters coming in from people all over the world saying how much this or that helped them. And frankly that feeling of being able to kind of surprise people with what they’re getting for free was so rewarding.


KHAN: That’s better than any amount of money that you can frankly get. I said, hey, if I can support my family doing this somehow, I’d rather this be more of kind of a service for folks. And so we set up as a not-for-profit, and not just as a not-for-profit. You know, we’re pretty committed to free as long as we can keep the lights on.


KHAN: Most of our capability to keep it free, because we got to pay salaries and real estate and server costs and all of that is through donations. A lot of people, over 100,000 people donating every year.


KHAN: Anyone listening, every dollar counts.

GONZALEZ: I am one of your donors, actually.

KHAN: Oh, thank you so much.

GONZALEZ: I did a search in my email for the stuff about this interview, and in, I just searched under “Khan” and I found one that thanked me for donating. I thought, oh wow, look at that.

KHAN: Well I’ll thank you in person. Thank you so much. I’m serious. That means a lot, because you know, there’s a lot that people don’t have to do, but that makes a big difference for our ability to keep doing what we do.

GONZALEZ: Well, it’s how I feel about, yeah. PBS and NPR and you guys and a lot of things out there that we take for granted that yeah, they’re not actually free to you to run. So yeah. So lately over I don’t know exactly how long, but you have started to add on this mastery learning component, and that’s really what we’re here to talk about. So explain how this mastery learning system works within Khan Academy.

KHAN: So from day one, this goes back to when I was working with my cousins. Just intuitively it felt that a lot of them, the reason why they were having trouble in, say, algebra, it wasn’t because they weren’t capable, it wasn’t because algebra was difficult, it’s because they had gaps in their knowledge from fifth grade.


KHAN: They forgot how to divide decimals, or from seventh grade, they were a little bit weak on their negative numbers with exponents. And so intuitively I said hey, look. If I can give them practice so that they can remediate those gaps, then they’re more likely, then algebra’s hopefully going to be a little bit more intuitive. And as I went on that journey with my cousins, simultaneously I started learning, hey, I’m not the first to think of this. Arguably it’s the oldest way of learning, that you should learn at a pace that’s comfortable for you and then master concepts as you go on. Benjamin Bloom famously coined this in the ‘80s in his famous 2 Sigma study where he showed that if students are able to learn at their own time and pace in a mastery learning framework, which to him he defined as a framework where if the student’s at 70 percent or 80 percent correct, that they should have as many chances as necessary to get to 90 percent-plus correct. That if students learn in that type of framework, personalized and mastery-based, that the same student at the 50th percentile could now be two standard deviations higher than that. And that was a big seminal study. It’s taught in ed schools. Everyone knows about it. But I think it was just kind of shelved, and there’s been over 300 studies since then about mastery learning. It’s actually one of the most robust views in education. No one really intellectually disagrees with it.

GONZALEZ: Right, right.

KHAN: The issue is the pragmatic, how do you implement it?


KHAN: When Benjamin Bloom was doing this study, the only way to frankly do it was with a personal tutor, which is not practical for most folks. And so what’s exciting is as Khan Academy started getting off of the ground and doing what it did, we realized there’s a very surreal, strong convergence between our beliefs and Benjamin Bloom’s beliefs. And so what we’ve launched, we’ve always had things that were going in this direction, but what we launched recently is a full mastery learning framework that is pretty much Benjamin Bloom’s vision, not my vision, where students are able to go as early as kindergarten all the way through college-level math or science or also in the humanities now, learn at their own pace, and get as much practice and support as they need to get to 90 percent, and then they’re able to move on to the next unit or to the next course. And all of this is with support of teachers. We were building the tools so that teachers could use it. You know, as we do Khan Academy, yes, there’s a lot of kids in the world who might not have access to a teacher if you’re in a village someplace in India, but the best world is these tools do what they do, but it really empowers a teacher to be able to go even deeper and to do focused intervention. So the Khan Academy is at its best when it’s paired with, and it’s in support of an amazing educator.

GONZALEZ: Right. Describe for me a little bit of what it looks like from the teacher end. Does it start with a sort of pre-assessment of a bunch of skills and then the platform will tell the teacher where each student needs to be, where the gaps are?

KHAN: It could be depending on the context. So if I’m a teacher, and let’s say I have a bunch of seventh-grade students, and I feel fairly confident that they’re at grade level, I can start the students at the seventh grade course on Khan Academy, and then they could progress forward at grade level, but they’d all be at their own time and pace, mastering concepts. They can do things like take unit tests and then course challenges, and they get successive levels of mastery that make sure that you’re not just doing the skill in a very narrow context. You’re also doing it in a mixed context where you’re having different questions, and the students have to identify, you’re getting some form of spaced review. If a teacher feels that, you know what, some of my students, even though they might be in seventh grade, they do have gaps in fifth and sixth grade, then I would actually recommend start them at the fifth grade course, and if the student feels, okay, I kind of know some of this, they could immediately go to the course challenge. And when you take the course challenge, it’s a course level thing, and then whatever they get wrong, they can drill in on those units and those skills, and then they can take the unit challenges and then drill into those skills. So that would be a kind of mechanism to do it for someone who knows, who has gaps but knows some of the material.


KHAN: And so it depends on the class that we’re talking about. But we want to support all of these cases.

GONZALEZ: Got it, got it. What content areas, I’m assuming that you don’t have mastery learning available for all of the content that’s currently on Khan Academy. So what’s already in place and what are you working on next?

KHAN: It’s already in place for kindergarten through college-level math. That includes calculus statistics, it’s in place for our high school and early college-level sciences. So that would be physics and biology. We’re hoping to have that in place in chemistry in the next year. We already have a lot of instructional assets in chemistry, but we don’t have the mastery learning framework yet. It is in place for our AP American government and politics course. It’s in place for our micro-economics course and our macro-economics course. So that’s where it is. And our hope is we’re actually hoping to pilot a first version of our, of a grades three through eight English and language arts mastery learning framework so students can get practice in reading comprehension. That we’re hoping to do for back to school. We also, the master learning engine is also what’s going on underneath in some of our partnerships around SAT practice, LSAT practice, and now we’ve also, the Praxis.


KHAN: Which teachers need to take to sometimes to get their jobs, and so we want to make sure that we’re supporting teachers with master learning as well.

GONZALEZ: Okay. And I should also note just for people listening that we are talking right now in February 2019. I’ve got listeners who might be listening two years from now. So there should be a lot more, you know, if this is later on. What are the next things you’re going to be tackling for master learning?

KHAN: So our vision is all of the core subjects from pre-K through the core of college, we view that as a trunk of someone’s education, not just in math but in science, in the humanities, we want to be able to support as well as we can in the modalities that we can deliver online and where we can’t, and there’s a lot of things that we can’t do where you absolutely need an amazing human being in a student’s life, we want to build the tools to support those teachers and to support the school leaders or the district officials. So I would say over the years to come, expect to see Khan Academy fully fleshed out in all of these subject areas. The mastery learning goes much deeper on the English and language arts and humanities side of things. I would expect to see even progressions in science that start much earlier than where we start right now. And the tools for the teachers and the district officials are hopefully only going to get better and better.


KHAN: And that’s just in English. Above and beyond, there’s over 30 translation projects of Khan Academy, Spanish and Brazilian Portuguese are the ones that are most robust already. Already is a fully Spanish version of everything I’ve just talked about.

GONZALEZ: Oh, no kidding. Okay. I did not know that. That’s great. Speaking of having an amazing human being and things that Khan Academy can’t do, I know that you have a school. And so I’m thinking that people listening or even seeing that I’m doing an interview with you on the podcast, I know there’s a large segment of educators, and I would probably include myself in that, I’ve got three kids in elementary school, who are concerned about kids basically sitting in front of screens all day at school and not even having any interaction with other people or anything, having basically their whole program just be digitized and automated. So what is your vision for how your mastery learning platform fits into a more well-rounded, dynamic, interactive educational environment?

KHAN: I would include myself in that group.


KHAN: The way I see it is I think there’s some folks from the technology world who think technology first. So they’re building a tool in solution of a problem. So they’ll say, look at this cool thing I made. Now how do I convince everyone to use it? I do not think that’s a good approach. I think the approach is what are the problems we’re trying to solve? So for me, when I think about what a school could look like, I say, okay. Teachers need better information so that they can focus their efforts. Students need better feedback, and they need to be able to adjust to their pacing. We need ways for class time to be more active and human, so that you can have more interaction with the humans and your peers, the teacher, not less. So those are kind of my design objectives when we think about Khan Academy. And so okay, so what will be useful things to do that? And there are things that you could do, and we’ve seen, and even in our lab school, we use a white board to make sure that if one student needs help for another, how would they get that help? We use the classroom space in a way that a teacher is able to easily find, figure out hey, how do I support this student? What’s their likely gap? Or how do I get another student to support that student?

And the tool is only valuable where it’s valuable, which is in my mind it’s more valuable for a teacher to be able to do that human intervention than to have to spend hours every night grading and assigning. So that’s where the technology’s very valuable. If a student is confused on something, and if a hint on a problem or an on-demand, three-minute video can unblock the student, great. That allows, once again, the teacher to have more capacity to either do a deeper intervention with that student, a kind of focus on the social emotional side, or do high-order tasks in the classroom, projects, simulations, etc., etc. So the whole point of me working to start a school like this is to show that it’s not, you know, trying to create some type of dystopian, Borg, Vulcan reality of kids in front of computers and just becoming these automatons. It’s actually the opposite. I actually think an appropriate use of technology, you’ll actually see kids interacting more, you’ll see students and teachers feel more alive, because there’s more human interactions. And I think anyone who visits our lab school, that’s the thing that surprises them is that it’s not kids in front of computers all day. It’s kids collaborating and interacting.


KHAN: And working alongside teachers. And yes, they use technology, but the technology is in service of a higher ideal, not just for the sake of technology.

GONZALEZ: Right, right. And I’ve seen the pictures. It does not look like “The Matrix” at your lab school, with people all just plugged into machines the whole time. Can you tell me a little bit about the results that you’ve seen already? I know that there are some schools, there’s one particularly in Philadelphia that have been using your mastery program with consistency. What kind of results are they seeing?

KHAN: This is the interesting thing. In the early days, this is all theoretical. We looked at all the studies from Benjamin Bloom and all of the other mastery learning studies. But as early as 2012 we started having third-party studies on Khan Academy. There was a Gates-funded, SRI Research did one back in 2012. The Albertson Foundation did one in Idaho, and this was with I think over 5,000 students. Those are already showing some pretty robust results. The one in Idaho was showing that if students completed 60 percent of a course in a mastery learning framework on Khan Academy that they were growing 1.8 times as much as their peers in that same amount of time, and this was using assessments like the NWEA MAP growth, which measures kind of cross-grade level growth.

And so that was, this is great, let’s all move to a mastery learning framework. Now that’s easier said than done. There’s a lot of, I know, every teacher I talk to, they intellectually agree with the idea. But there’s a lot of things around them that make it difficult to move overnight to that. What’s been exciting is this recent round of studies, and it sounds like you’ve heard about the one from Centennial outside of Philadelphia, we’re seeing more consistent that 30 minutes to 60 minutes a week, if students are able to do mastery learning at that level, that even that is resulting in 20 to 30 percent greater than expected growth for students. And we not only saw that in Centennial, Long Beach, in the LA area ran a study where they saw that the classrooms that on average were reaching thresholds like that, they were twice as likely for their students to be at grade level. We’ve seen on some of our work with the SAT, the students who were able to put in 20 hours over the 18 months between the PSAT and the SAT, so it’s 20 hours but over a very long period of time, so it’s not a lot of time, they saw twice the expected gain from the PSAT to the SAT. There are studies actually in Brazil, and these were studies where the classrooms in the experimental group did one hour of personalized practice in a master learning framework, they saw 30 percent greater than expected growth. So there’s been a bunch of data points that make us feel really good. And when we talk to teachers now, it’s like hey, we think one hour could already make a really big difference.


KHAN: The teachers are telling us, hey, this feels very doable. Because the teachers have incredible pressures on them. Every teacher I talk to, they’re telling me, look, I know I have children in my room who are not ready for the standards I need to cover. But I need to cover them. And I also know there are some kids in the room who might already know some of those standards, but I still have to cover those standards. So they’re kind of stuck between a rock and a hard place, and I think what’s interesting is there’s a way that we can start to have a little bit of our cake and eat it too, which is maybe three or four days you do more of a traditional model, so you can ensure that coverage is happening, that everyone is having exposure to grade level material, but one class period a week can be focused on that personalized practice. For some students that will be remediation. For some students that will be reinforced practice and for some students it will allow them to accelerate. And to me it’s not kind of, it’s not voodoo that it’s having these gains, because we’re seeing that the students are doing a far larger number of questions where they’re getting feedback, and they’re operating in their zone of proximal development, when they’re doing even an hour a week of this. So we’re excited about partnering with a whole bunch of more teachers and principals and districts to see how we can essentially unlock, and it sounds like an informercial, but how do we unlock the power of mastery learning for every child in America?


KHAN: We’re not selling anything.


KHAN: We’re free. But I really think there’s a huge opportunity here.

GONZALEZ: Yeah. Well and I think probably the most interesting thing I’m hearing, apart from the great results is that people are seeing good results even without having to do even that much of it. So any teachers that are listening thinking, oh, I’m not sure I’m ready to switch over to a whole new system. You don’t have to do that. You could just choose a small chunk of the week.

KHAN: Exactly. And I want to keep reinforcing it. I think a lot, one of the things I often get. I remember actually I once presented to both congressional caucuses, this was a couple of years ago. And one of the congress people stood up and says, hey, why do they let you in here? You’re here selling — I’m like, no, let me just be clear. This is free, not-for-profit. I don’t own Khan Academy. I don’t get, in fact the more folks that use it, I have to go do more fundraising, because our server costs go up. We’re here to drive impact for students. If we can’t do that, we shouldn’t be doing what we’re doing. And so I think that’s a — and then on top of that, we think there’s a way that we can serve teachers so that they can meet the individualized needs of students without having to sacrifice the kind of grade level practice.

GONZALEZ: Right, right. If a teacher wants to learn more about this, where do they go? They just go to Khan Academy and they’ll see it? Or is there a section just for mastery learning?

KHAN: They’ll go to Khan Academy. If you sign up as a teacher it’ll ask you a few questions about what classes you’re trying to teach and how you’re trying to teach it. There’s also supports for kind of teacher-directed assignments through Khan Academy where those, we kind of view those as auto-graded worksheets. But we’re hoping that the teachers really do experiment with the mastery learning. The teachers we’ve worked with really enjoy it. And if there’s teachers out there who aren’t, let us know. We’re in this to see how we can support teachers, so that they can, because they’re the ones at the end of the day who are really supporting the students and doing the hard work day-in, day-out. So our goal is to see what tools we can make to make their lives a little bit easier and their students’ lives a little bit easier.

GONZALEZ: Fantastic. Anything else you want to share about the program before we wrap up?

KHAN: You know, I’ll just leave it on a, I always talk about Khan Academy in three phases. That first phase was me kind of bumbling around and operating out of a walk-in closet with my family members with some nascent ideas. I think the second phase was when I had kind of gone with both feet in and dove into it and folks came out of the woodwork to help make it happen. We got a lot of really amazing teachers and educators helping out this effort. We have thousands of people who volunteered. We have a whole ambassador program of teachers who are helping other teachers kind of unlock what they could do with this. The way I tell the team here at Khan Academy and all of our stakeholders and the hundreds of thousands of people who donate is you know I think we’re at a unique opportunity right now, that if 400 years ago you went to Western Europe and you saw who’s literate, you would have seen about 15, 1-5, percent of the population knew how to read, about 20 percent of men, 10 percent of women. And I suspect that if you ask someone who did know how to read, say a member of the clergy, what percentage of the population think is even capable of reading, they might have said maybe 30 percent. But you fast forward now, you know, it would have been a widely pessimistic prediction.


KHAN: Pretty close to 100 percent can read, and that’s because of the, you can almost say the miracle of mass, free, public education that happened in the 18th and 19th centuries. Now we’re at another inflection point in history. That was the industrial revolution. Now people talk about what’s going to happen with 21st century, with the need for, you know, labor is facing threats from automation and globalization. All of these things, how do we get more kids to be in that top of that pyramid and that creative class, to help push forward the frontiers of medicine and science and art? And I think if I ask a lot of people today, how many people would think are capable of being, contributing to cancer research, they might say, maybe optimistically 10 percent? But I think that’s kind of similar blinders on. And I genuinely believe that the task at hand, it’s not just nice to have. We want to work with educators around the world to figure out how do we get it so that most kids, like literacy, we get to a world where we can shock ourselves in an optimistic way that most people are going to be able to participate in the fullest way possible in society and advance what we are as a species together.

GONZALEZ: That is a great vision. That is a great vision. Hopefully this will get a lot of people to come over and see what you’re doing and take advantage of all you’re offering. Thank you so much, Sal, I really appreciate your time.

KHAN: Thank you. Thanks for having me.

For links to all the resources mentioned in this podcast, visit, click podcast, and choose episode 116. To get a weekly email from me about my newest blog posts, podcast episodes, and products, sign up for my mailing list at Thanks so much for listening, and have a great day.