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Comment by yummyfajitas | Hacker News Reader

The main criticism of the article is a bit silly:

Khan will put the video out there and see how people react to it. He perceives this to be a better approach than incorporating results of quality research projects into his instructional decisions. In the age of No Child Left Behind and its mandate for “scientifically based research” as the foundation for classroom instruction, this seems lazy.

Yes, Khan is doing his own scientific research, on the theory that he does a better job than the educational establishment. This might be arrogant (given the quality of educational research I've seen, I don't think it is), but it isn't lazy.

As for the claims that Khan does a worse job than other teachers, no data is provided to back this up. Just vague claims that if he did something different, he might get better results.

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I don't think so at all. The author supported their claim with that indicate Sal Khan doesn't fully recognize the impact of PCK, and gives specific examples in Khan's lessons.

While PCK is a "buzzword", it does represent something very real in learning: That Instructors (be they amateur or professional) must understand the hidden challenges of the material they teach. Specifically, in ensuring that misconceptions do not propagate and embed themselves into a pupil's mind. In math, misconceptions can be particularly troublesome as the facets of mathematics, particularly at the elementary level, carefully layer on top of each other.

If you want an example of this that falls into the sphere of stuff closer to HNs, look to Zed Shaw's Learn Code the Hard Way series.

Shaw puts exercises and examples in front of readers designed explicitly to prevent the reader from developing weird misconceptions about the way a programming language (or programming in general) works. That's often why readers will say things finally "clicked" when they work through his material. Shaw may not be familiar with the buzzword term "PCK" but he definitely recognizes the challenges in teaching each concept he presents to the reader. You can see part of this come through with his critique of K&R C.

But just "putting the video out there and seeing how people react to it" isn't "scientific research." Science involves testable hypotheses and controlled experiments. Just throwing things against the wall and seeing which ones stick is something different.

"Putting the video out there" is an experiment. It's not rigorously controlled, but it's about as controlled as a website is likely to get. So they put something out there, see how well it works, and maybe tweak it.

That's the very essence of scientific experiments. You don't always need a "hypothesis" to do science. (Or, if you like, the hypothesis is "This video will teach students to do X.")

Khan has a fairly extensive testing/data analysis system. He puts the material out there, measures whether students correctly answer the problems, and iterates from there.

While it's not controlled experiments, it's about as close as you can get in education.

Meant to reply to this, but didn't work, so copying and pasting:

In the debate about khan academy, there's an important fact that is continuously missed, it's not about effective instruction vs. ineffective instruction; it's about less effective vs. more effective.

The khan academy way may be better than trying to learn from the lower X% of math teachers out there. It's highly unlikely that it's going to be better than the top Y%.

Things like Khan academy will not "fix" education. Anything that standardizes and automates education will only do one thing: insure mediocrity. It will protect against the bad while eliminating the possibility of excellence.

The problem with education in the US is cost - quality is almost as good as it possibly could be (holding the inputs fixed).

In 2010, the US government spent $900B on education. If Khan can reduce the number of teachers needed by even a few percent, that's a HUGE savings.

In 2010, the US government spent $900B on education. If Khan can reduce the number of teachers needed by even a few percent, that's a HUGE savings.

Fully agreed with the conclusion. Staff compensation (including SUBSTANTIAL nonsalary compensation) is a big part of the budget of any school. Making the work of teachers more efficient (in the economics sense of "efficient") helps free up money for other worthy purposes.

Another comment to your comment doubted the figure, I think because you wrote "US government spent" when you perhaps meant "all levels of government in the United States spent" so much money on education. Most spending on schools in the United States is from state taxes (as in my state) or from local taxes (as in some other states), as I'm sure you already know but which may be news to onlookers from other countries.

"The U.S. has more than 14,000 public school districts and spends more than $500 billion on public elementary and secondary education each year (combined spending of federal, state, and local governments)."

http://www.census.gov/did/www/schooldistricts/

"United States

(Billions of dollars. Detail may not add to total due to rounding)

Total Federal State Local

593.7 74.0 258.2 261.4"

http://www2.census.gov/govs/school/10f33pub.pdf

in 2010, the US Department of Education budget was $47 billion [1]. That's between 1-2% of the total budget. The problem with education in the US is not cost, and even if it was, the solution is not 'get rid of a few percent of teachers."

Where did you get that $900 billion number?

[1] http://en.wikipedia.org/wiki/2010_United_States_federal_budg...

This doesn't include state and city levels, where most of the education spending happens.

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