How to teach

Salman Khan’s Khan Academy is an amazing labour of love, if you haven’t come across it. Over a thousand video tutorials, each around ten minutes long, on subjects ranging from calculus and statistics, through biology, to modern history.

But this is what’s really mindboggling: while skimming the list of topics, and pondering the immensity of the undertaking, you might wonder how many experts contributed, and how anyone could have the stamina to organise it all — until you discover that all the tutorials are presented by the one guy.

It all started when Khan tutored his cousin in maths, at first face to face, but later via Youtube just using Microsoft Paint. Struggling students discovered the clips and begged for more.

According to the testimonials, academics have begun directing their students there, and it’s easy to see why. I would send mine to the finance ones. They deal with a number of technical topics engagingly, but even more useful is the series on the financial crisis and the US bailout. Francis, aged 12, had high prasie for the series on the French Revolution.

There’s more background in some PBS and CNN profiles linked at the top of the home page. What I’d like to emphasise here is what this approach tells us about effective teaching. Whatever you might say about the clips, they are not polished. He uses a humble drawing software, scribbling and crossing out, and improvises his script, humming and hawing his way through examples he makes up on the spot.

One might be inclined to conclude that the tutorials are effective despite the informality, but I think it’s because of it. Khan is quoted thus:

If you’re watching a guy do a problem (while) thinking out loud, I think people find that more valuable and not as daunting.

Exactly. It’s more natural. As any decent teacher knows, students pay more attention when you stumble and bumble through a topic using chalk and talk, because they feel they’re participating — active partners in a process of thinking something out. You’re talking with, not just to them, let alone at them. If you make some slip-ups along the way, so much the better. And how many teachers have had the depressing experience of discovering that when a student is sitting in your office, motivated by an impoending exam, you can easily explain some concept to him in a ten-minute, improvised session, that he failed to grasp from several hours of your elegently crafted lectures.

In Keynes’s essay on Marshall he quotes Mary Marshall:

He said the reason why he had so many pupils who thought for themselves was that he never cared to present the subject in an orderly and systematic form or to give information. What he cared to do in lectures was to make students think with him.

He adds his own recollection:

I remember Marshall telling me that if he saw a man taking detailed notes at one of his lectures, he wrote him off as a fool: but that if he had reason to believe that the individual in question was a man of ability, he would have regarded it as a personal insult.

Returning to the current century: show your students a polished video or PowerPoint show on some technical topic, where every point is handed down with military precision and confidence, and their eyes will glaze over in no time. This applies with even more force to presentations by students for students. The first rule you give them — DO NOT READ FROM A SCRIPT — is the first one they want to break. ‘But we’re too nervous!’ ‘I won’t be able to remember how the explanation goes!’. Yes, I know, and that’s precisely why your classmates will be payiing attention and trying to figure it out for themselves.

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Edward Mariyani-Squire
Edward Mariyani-Squire
11 years ago

students pay more attention when you stumble and bumble through a topic using chalk and talk, because they feel they’re participating — active partners in a process of thinking something out.

Couldn’t agree more. I suppose the good ol’ Powerpoint is a crutch to lean on, but it is certainly true (or at least I get the very strong impression it’s true) that a lecture only really comes alive when some poor soul interrupts to ask, “Why is that?” For some reason, when moving into “Thinking On One’s Feet” mode, one’s explanations become clearer, one’s examples become more interesting – and sometimes quirkier – and one’s asides become funnier.

Chris Lloyd
Chris Lloyd
11 years ago

I didn’t look at the other stuff on physics and finance, which may be fantastic for all I know. But I am extremely underwhelmed by some of his statistics tutorials. The whole idea of population and sample is incredibly archaic and hardly applicable to anything (except opinion polls). If I look at a weekly time series of share prices of 10 stocks for the last year, where exactly is the population? How about the median house price for this month in Surrey Hills? You will tie yourself in knots if you try to say what the population is.

Really 1970s stuff. He will be explaining degrees of freedom and sums of squares next.

The standard error of the mean (SEM) tutorial was also pretty standard and old fashioned. The best way to explain SEM is to use XL for real time simulations. Students never click to what the SEM measures until they see the mean actually vary. He does use a simulator towards the end, but you just see the final distribution of the mean – you do not see the means being generated.
So more power to the guys for the concept, but the execution on the two tutorials I sampled was lacking I am afraid.

James Farrell
James Farrell
11 years ago

Thanks for looking, Chris. Given the range of topics, I’m sure some ar done much better than others. I agree comepletely about Excel as as a tool for teaching statistics and econometrics, but it might be hard to employ it in this Youtube format.

conrad
conrad
11 years ago

“The whole idea of population and sample is incredibly archaic and hardly applicable to anything (except opinion polls)…He will be explaining degrees of freedom and sums of squares next.”

I must admit to not quite getting what you are trying to imply — these concepts are still used commonly in many areas of science and I don’t see why you wouldn’t teach them or what’s wrong with them (I realize population data is hard to find, but it’s out there — Census data would qualify — but it’s also worthwhile knowing what a population is so that you know what a sample is). If, example, I wanted to see whether program X in school Y worked better than program Z, how would you expect people to compare them? I’m not saying here that there might not be better ways of doing statistics, but you need to teach what is typically used.

munroe
munroe
11 years ago

The whole idea of population and sample is incredibly archaic and hardly applicable to anything (except opinion polls).

Opinion polls are the public face of statistics. But just to give some other examples that are used a lot: average life expectancy, median wage, average IQ, average cholesterol count, average number of sexual partners,…
It’s not an archaic concept, any more than solving quadratic equations, or Einstein’s Theory of Special Relativity, are archaic concepts.

The best way to explain SEM is to use XL for real time simulations.

I would like to see this style of explanation. Please make a youtube video of it. Seriously.