Let me start by saying I don't have much control over how I teach my course: I'm told how to organize student desks, that I need to use the flipped classroom model, that classroom time is mostly for solving problems (no traditional lecture), and that videos need to be part of the course. Administration loves Khan Academy, so I've seen quite a few of the videos. I've been a little surprised by the passion with which these videos have been pushed. Ignoring some of the errors that occur (it happens to everyone), Sal Khan does a good, solid job at explaining the material (but not great). I attributed Khan's success to the fact that he explained math using videos which allowed students to pause, rewind, and play them over and over when they were ready to learn. "Education on demand", if you will.

Lately, though, there's been a definite backlash to Khan Academy videos unfolding. The first step was this video. It seemed like a cheap shot at the time but perhaps it was, with hindsight, the opening salvo of the I-don't-like-Sal-Khan club. I say that because you can see what unfolded here. Reporter Valerie Strauss reported, "...educator Dan Meyer and Ed Week opinion blogger Justin Reich, noting that there are errors in some of the Khan Academy videos, have started a contest inviting readers to critique the academy lessons.". All this was a prelude to a post by Marion Brady which is critical of the Khan Academy style of teaching. Brady was balanced enough to give some praise along with his criticism of Khan before saying, "Yes, Khan is good. In the kingdom of the blind, the one-eyed man is king." followed by "But a lecture is a lecture.".

But the criticism got sharper and filled with a lot more cheap shots in this piece by Karim Kai Ani, the founder of a Mathalicious. After listing many of Khan's accomplishments he starts his attack: "Khan Academy boasts almost 3,300 videos that have been viewed over 160 million times. That’s a heroic achievement. But there’s a problem: the videos aren’t very good.". The first problem he finds: "Take Khan’s explanation of slope, which he defines as “rise over run.” An effective math teacher will point out that “rise over run” isn’t the *definition* of slope at all but merely a way to calculate it.". Really? I thought "rise over run" was a verbal description of what the slope is and the way to calculate it is $latex \frac{y_2-y_1}{x_2-x_1}$ where $latex (x_1, y_1), (x_2, y_2)$ are the points used in calculating the slope. The real problem seems to be personal for Karim Kai Ani says, "...effective teaching is incredibly complex. It requires planning. It requires reflection. And it certainly requires more than just “two minutes of research on Google,” which is how Khan describes his own pre-lesson routine.". Whether Khan spends 2 minutes or 2 hours is immaterial, the only criteria should be on the presentation itself. That personal attack boils over here: "Of course, teachers aren’t “pissed off” because Sal Khan is the world’s teacher. They’re concerned that he’s a bad teacher who people think is great; that the guy who’s delivered over 170 million lessons to students around the world openly brags about being unprepared and considers the precise explanation of mathematical concepts to be mere “nitpicking.”". Again, really? How does Karim Kai Ani know what all those teachers are upset about and that none of the attacks are due to jealousy? Have they all told him? No, of course not. To be clear, here are some valid points such as "Khan himself says that “math is not just random things to memorize and regurgitate,” yet that’s exactly how his videos present it." but most of his criticism is nit-picky. On his website he claims: "Instead, the real issue with Khan Academy is its underlying pedagogy (or lack thereof). Quite simply, it doesn’t work. Not only do we know this anecdotally — how many adults still say “I don’t *do* math?” — but we also know it experimentally. In fact, we’ve known it for decades!". Strange: 170 million views with lots of teachers singing Khan's praises not that long ago. All those professional teachers found merit but they can't be right (even if they are professional teachers). As they say in sporting events: "SCOREBOARD!".

Khan has recently responded with a video and in an article (together with Karim Kai Ani counter response) here. With respect to the article, Sal picked up on some of Karim Khai Ani's mistakes but I think the part that really stood out to me apart from Karim Kai Ani repeating personal attacks (eg 2 minutes of preparation) was here: "This is actually a very interesting question, and one we teachers were debating at Twitter Math Camp: C*an you describe slope without units?" *followed by "On the other hand, does this mean that units are absolutely* necessary*?" and "According to Sal, the units are the same (feet) and would therefore “cancel,” leaving a slope of 1.5. But is this correct: is a vertical foot really the same as a horizontal foot, or do they in fact describe two very different things? There’s no simple answer. And that’s okay." followed even later with "Of course, others may disagree, and indeed other teachers *did *disagree. *Does slope require units?* Some said yes. Others said no. What Sal said, though, was, “you’re wrong.” This seemingly defensive attitude is antithetical to effective teaching.".

I have to admit to being flabbergasted at this point. Khan has just canceled the meters in the numerator with the meters in the denominator and is being questioned by a professional: "Is this correct?" followed by "There's no simple answer".** Yes, there is: it's correct**. Are we now to make a distinction between vertical feet, horizontal feet, feet measured on an angle and feet measured along a curve? When we calculate the radius of a circle do we worry about whether the distance from the center to a point on the circle is left to right or down to up? If you think that's important and we carry those units "vertical meters" into the formula to get the circumference $latex 2\pi r$ then the units for the circumference are now vertical meters. Sal knew the correct answer, stated the correct answer and is now being subjected to carping by someone who should know better.

I also find it disturbing that not all the math teachers know you can cancel units and this illustrates a point I've made before: there are many people teaching math who don't have mastery of the subject who are "qualified" to teach because they have passed the certification requirements.

With over 3,000 videos there will be mistakes and explanations that are weak. The same could be said of the lessons any teacher has given over the course of the year. With over 170 million views, many students have Khan videos worthwhile and helpful. Had his videos not been helpful to millions of people he would not have gotten as popular (and over hyped) as he has. His use of technology in teaching connected and, strangely enough, no "proper" teacher had the vision or inclination to do it first. And he selflessly put out his videos for free so they could help others in stark contrast to others running for profit sites. As someone running a website, my experience is that it's not that expensive.

The truth is, Sal would be as good as (if not better) than many math teachers that are working in the classroom yet, without any proper teaching experience, he has connected with and touched the lives of more students than his detractors. He's even helped change the way people view education more than most educators have...in his spare time. I respect what he's done and think he deserves better treatment than many "professionals" are giving him.