The One World Schoolhouse: Education Reimagined

by Salman Khan

  At once, I saw that the idea was… ridiculous! YouTube? YouTube was for cats playing the piano, not serious mathematics. A serious, systematic curriculum on YouTube? Clearly, a harebrained notion.

  Some three thousand videos later, I still wish I’d thought of it myself.

  No-Frills Videos

  In character, in manner, in style, in all things, the supreme excellence is simplicity.

  —HENRY WADSWORTH LONGFELLOW

  To those who believe that quality education requires showplace campuses and state-of-the-art classrooms, and is therefore a luxury item available only to wealthy communities in wealthy countries, I’d like to point out a few things about the early days of the Academy. For example, our headquarters was first a guest bedroom and then, more famously, a closet. True, it was a walk-in closet, with electrical outlets, room for a small desk, and even a window overlooking the garden. But it was a closet nonetheless. I thought of it as a kind of monk’s cell, a place to concentrate without distractions or the temptations of too much comfort.

  In the formative years of the Academy, I was still muddling my way toward the most effective methods for presenting the video lessons. I was guided in part by my own taste and temperament, which tended toward the austere.

  Early on, for example, I decided that I wanted the background of my computer “chalkboard” to be black. Even though it was now virtual, I felt that there was something magical about a blackboard. One of my key hopes was to remind students of the excitement of learning, to bring back the fun and even the suspense that ensued when the quest for understanding was seen as a kind of treasure hunt. What better way, graphically, to suggest this than by showing problems and solutions seeming to emerge from the void? Knowledge brought light out of darkness. With application and focus, students found answers where before there had been nothing but a blank.

  Another formative and crucial decision had to do with the duration of the lessons. Back when I was tutoring Nadia over the phone, we had no particular time constraints. We talked until one or the other of us had to go, or until a certain concept had been covered, or until a certain level of frustration or mental fatigue had been reached; the length of our sessions was not determined by the clock. But when I started posting videos on YouTube, I had to abide by their guidelines. Although their rules have now changed for certain kinds of content, there was then a ten-minute limit for what the site would post. So my lessons were just about ten minutes long.

  And it turned out that ten minutes, give or take, was the right length for them to be.

  Let me make it clear that I did not discover this fact. I stumbled upon it by a mix of intuition and serendipity. But the truth is that well-credentialed educational theorists had long before determined that ten to eighteen minutes was about the limit of students’ attention spans.

  Back in 1996, in a prestigious peer-reviewed journal called the National Teaching & Learning Forum, two professors from Indiana University, Joan Middendorf and Alan Kalish, published a remarkably detailed account of the ebbs and flows of students’ focus during a typical class period. It should be noted that this study centered on college students, and of course it was done before the age of texting and tweeting; presumably, the attention spans of younger people today have become even shorter, or certainly more challenged by distractions.

  In any case, breaking the session down minute by minute, the professors determined that students needed a three- to five-minute period of settling down, which would be followed by ten to eighteen minutes of optimal focus. Then—no matter how good the teacher or how compelling the subject matter—there would come a lapse. In the vernacular, the kids would “lose it.” Attention would eventually return, but in ever briefer packets, falling “to three or four minutes towards the end of a standard lecture.”1

  An even earlier study, from 1985, had tested students on their recall of facts contained in a twenty-minute presentation. For purposes of scoring, the researcher broke the presentation into four segments of five minutes each. While you might expect that recall would be greatest regarding the final section of the presentation—the part heard most recently—in fact the result was strikingly opposite. Students remembered far more of what they’d heard at the very beginning of the lecture. By the fifteen-minute mark, they’d mostly zoned out.

  My point here is that long before Khan Academy or YouTube even existed, solid academic research had gone a long way toward describing the length and shape and limits of students’ attention spans. Yet these findings—which were quite dramatic, consistent, and conclusive, and have never yet been refuted—went largely unapplied in the real world.

  Curiously, in the Middendorf and Kalish study, even the researchers themselves shrank from applying their own conclusions. Having established that students’ attention maxed out at around ten or fifteen minutes, they still regarded it as a given that classroom sessions lasted an hour. They suggested, therefore, that teachers insert “change-ups” at various points in their lectures, “to restart the attention clock.” Perhaps, in the hands of skilled and resourceful teachers, these “change-ups” were effective in refreshing kids’ focus. Still, there was something gimmicky and beside the point about the whole idea; it went directly against the grain of the findings. If attention lasted ten or fifteen minutes, why did it remain a given that class periods were an hour?

  Or again, if the “change-ups”—things like small-group discussions or active problem-solving—recharged student focus, why was the broadcast lecture still the dominant mode? Why was it still presumed that students would spend most of their day passively listening?

  The bottom line is that the research—and, frankly, experience and common sense—pointed in a certain clear direction, but there was too much inertia to the already existing model to do anything about it.

  Now, there are some exceptions. Many college courses in the humanities focus on discussion over lecture. Students read course material ahead of time and have a discussion in class. Harvard Business School took this to the extreme by pioneering case-based learning more than a hundred years ago, and many business schools have since followed suit. There are no lectures there, not even in subjects like accounting or finance. Students read a ten- to twenty-page description of a particular company’s or person’s circumstance—called a “case”—on their own time and then participate in a discussion/debate in class (where attendance is mandatory). Professors are there to facilitate the discussion, not to dominate it. I can tell you from personal experience that despite there being eighty students in the room, you cannot zone out. Your brain is actively processing what your peers are saying while you try to come to your own conclusions so that you can contribute during the entire eighty-minute session. The time goes by faster than you want it to; students are more engaged than in any traditional classroom I’ve ever been a part of.

  Most importantly, the ideas that you and your peers collectively generate stick. To this day, comments and ways of thinking about a problem that my peers shared with me (or that I shared during class) nearly ten years ago come back to me as I try to help manage the growth and opportunities surrounding the Khan Academy.

  Focusing on the Content

  Art is the elimination of the unnecessary.

  —PABLO PICASSO

  The duration of the YouTube lessons is hardly the only instance in which Khan Academy teaching methods—arrived at largely by serendipity and intuition—turned out to be neither more nor less than the implementation of sound pedagogic research that had been accepted in theory but never really been applied. As we’ll see, this is a recurring theme.

  For right now, however, I’d like to introduce another factor that was a key consideration in shaping my approach to teaching: cost. I was bankrolling the Academy solely from my personal savings. I loved teaching, but I didn’t want to go broke doing it. When it came to posting the video lessons, I wanted to keep the equipment and production costs to an absolute minimum.

  It was partly for this reason�
��and not because of some preexisting theory—that I decided that I would never be pictured in the lessons. I didn’t at the time own a suitable video camera, and I didn’t want to buy one. It seemed like a slippery slope. If I had a camera, I would have to worry about the lighting. If I had good lighting, I would have to give thought to what I was wearing and whether I had spinach in my teeth. The danger was that the whole process would become more like making movies than tutoring students. Tutoring is intimate. You talk with someone, not at someone. I wanted students to feel like they were sitting next to me at the kitchen table, elbow to elbow, working out problems together. I didn’t want to appear as a talking head at a blackboard, lecturing from across the room. So it was determined that students would never see me but only hear my voice, while the visuals would be nothing except my scrawls (and occasional historic images) on the black electronic chalkboard. Students would see the same thing I was seeing.

  Human beings are also hardwired to focus on faces. We are constantly scanning the facial expressions of those around us to get information about the emotional state of the room and our place in it. We seem to be hardwired to meet each other’s gazes, to read lips even as we are listening. Anyone who has ever raised a baby has noticed its particular attention while looking at its mother; indeed, its parents’ faces are probably the very first things a newborn manages to focus on.

  So if faces are so important to human beings, why exclude them from videos? Because they are a powerful distraction from the concepts being discussed. What, after all, is more distracting than a pair of blinking human eyes, a nose that twitches, and a mouth that moves with every word? Put a face in the same frame as an equation, and the eye will bounce back and forth between the two. Concentration will wander. Haven’t we all had the experience of losing the thread of a conversation because we homed in on the features of the person we were talking with rather than paying steady attention to what was being said?

  This is not to say that faces—both the teacher’s and the student’s—are unimportant to the teaching process. On the contrary, face time shared by teachers and students is one of the things that humanizes the classroom experience, that lets both teachers and students shine in their uniqueness. Through facial expressions, teachers convey empathy, approval, and all the many nuances of concern. Students, in turn, reveal their stresses and uncertainties, as well as their pleasure when a concept finally becomes clear.

  But for all of that, the face time can and should be a separate thing from first exposure to concepts. And these two aspects of the educational experience, far from being in conflict, should complement one another. The computer-based lessons free up valuable class time that would otherwise be spent on broadcast lectures—a model in which the students generally sit blankly with no effective way for teachers to appraise who’s “getting it” and who is not. By contrast, if the students have done the lessons before the interaction, then there’s actually something to talk about. There are opportunities for interchange. This last point needs to be emphasized, because some people fear that computer-based instruction is all about replacing teachers or lowering the level of skill needed to be a teacher. The exact opposite is true. Teachers become more important once students have the initial exposure to a concept online (either through videos or exercises). Teachers can then carve out face time with individual students who are struggling; they can move away from rote lecturing and into the higher tasks of mentoring, inspiring, and providing perspective.

  This suggests something that is at the very heart of my belief system: that when it comes to education, technology is not to be feared, but embraced; used wisely and sensitively, computer-based lessons actually allow teachers to do more teaching, and the classroom to become a workshop for mutual helping, rather than passive sitting.

  Mastery Learning

  The nature of an innovation is that it will arise at a fringe where it can afford to become prevalent enough to establish its usefulness without being overwhelmed by the inertia of the orthodox system.

  —KEVIN KELLY, COFOUNDER OF WIRED MAGAZINE

  Before moving on from this brief introduction of some of the bedrock principles and intuitions upon which the Academy’s methods were founded, I’d like to mention one other important concept that will figure significantly in our story: mastery learning.

  At its most fundamental, mastery learning simply suggests that students should adequately comprehend a given concept before being expected to understand a more advanced one. While this seems straightforward and commonsensical enough, mastery learning has had a rocky and controversial history that is of interest for at least two reasons. First, it constitutes another instance of the education establishment failing to follow up on its own best research and soundest advice. Second, because of advances in technology, it is finally possible—nearly a century after the advantages of mastery learning were first described and tested—to broadly apply its methods and techniques to real schools and real students.

  Here’s a little history. Way back in 1919—before there were computers, or television, or antibiotics—a progressive educator named Carleton W. Washburne was named superintendent of schools in the affluent Chicago suburb of Winnetka, Illinois. The time and place were right for innovation. The victory in World War I had boosted national morale and helped create the American can-do spirit. Economic times were on the upswing; Winnetka was a manageably sized school system with the will and the means to experiment and excel. In 1922, Washburne introduced what became widely known as the Winnetka Plan.

  At its heart was the somewhat radical concept of mastery learning. What made mastery learning radical? Two things. First, it was predicated on the belief that all students could learn if provided with conditions appropriate to their needs; no one should have to be “held back” or put on a track that leads to academic failure.

  Second, mastery learning structured its curriculum not in terms of time, but in terms of certain target levels of comprehension and achievement. This turned tradition quietly but entirely upside down. In the traditional model, a certain amount of class time is devoted to a particular topic or concept; when the allotted interval is finished, the entire class moves on, in spite of the fact that individual students will have achieved widely varying degrees of mastery over the material. In Washburne’s system, by contrast, students, with the help of self-paced exercises, proceed at varying rates toward the same level of mastery. Those who learn more quickly can move ahead or do “enrichment exercises.” Those who learn more slowly are helped along by individual tutoring, or peer assistance, or additional homework.

  Let me emphasize this difference, because it is central to everything I argue for in this book. In a traditional academic model, the time allotted to learn something is fixed while the comprehension of the concept is variable. Washburne was advocating the opposite. What should be fixed is a high level of comprehension and what should be variable is the amount of time students have to understand a concept.

  During the progressive 1920s, interest in the Winnetka Plan ran high. Self-instruction “workbooks” were in demand around the country. Carleton Washburne himself became an academic star, going on to serve as president of the Progressive Education Association and to join the faculty of Brooklyn College. But then a strange thing happened to the notion of mastery learning. It soon went out of vogue, and for years—for decades—it was all but forgotten.

  Why? Part of the reason, no doubt, was economic. A small, wealthy school system like Winnetka’s could afford the new textbooks and exercise tablets and other materials required by the system; but the technology of paper publishing was expensive, and probably impractical on a nationwide scale. Then, too, there was the issue of teacher retraining; mastery learning did in fact call for a somewhat different set of techniques and skills, which in turn called not only for money but for initiative and flexibility on the part of teachers and administrators.

  Largely, though, what killed mastery learning, 1920s style, seems to have been simple
inertia and resistance to new and threatening ideas. In a truly shocking 1989 study, it was concluded that between 1893 and 1979, “instructional practice [in public schools] remained about the same” (and it really hasn’t changed from 1979 to 2012 either)!2 To be sure, some very innovative groups of teachers and schools have been experimenting with new techniques within their classrooms, but the mainstream model did not change in any appreciable way. Did no one notice how much the world was changing, and how much the educational needs of students were evolving as well?

  In any case, the concept of mastery learning seems to have been smothered under the vast weight of educational orthodoxy, and it languished until the next progressive era—the 1960s—when it was revived, in slightly different form, by a developmental psychologist named Benjamin Bloom and his leading protégé, James Block.3 Bloom and Block suggested refinements in testing methods and the delivery of feedback, but their basic principles came straight out of the Winnetka Plan. Students learned at their own pace, advancing to the next concept only after reaching a prescribed degree of mastery over the previous concept. Teachers served primarily as guides and mentors rather than lecturers. Peer interaction was encouraged; peers helping peers was of benefit not only academically, but in character-building as well. Some students might struggle, but none were given up on.

  Mastery learning techniques were soon being applied in various pilot programs around the country. In study after study, mastery learning kicked butt when compared to conventional classroom models.

  One research paper concluded that “students in mastery learning programs at all levels showed increased gains in achievement over those in traditional instruction programs…. Students retained what they had learned longer under mastery learning, both in short-term and long-term studies.”4 Another study found that “mastery learning reduces the academic spread between the slower and faster students without slowing down the faster students.”5 Shifting the emphasis from students to teachers, yet another study recorded that “teachers who [used] mastery learning… began to feel better about teaching and their roles as teachers.”6