How do you figure the circumference of a circle ?

And why would you want to do that ?

In his final week as Chancellor of New York's public schools, Mr. Joel Klein was interviewed on TV about his educational philosophy. Well, he opined, a child certainly must know how to figure the circumference of a circle.

Now I bet that Mr. Klein himself, a lawyer and educational administrator, never once had to figure the circumference of a circle after leaving high school. Perhaps he needed this knowledge for higher math in college, and perhaps not. I myself happen to remember the idea: 2πR, and of course I needed this knowledge when I studied trigonometry and calculus. So yes, I am not against teaching 2πR somewhere in high school, or, better yet, teaching how to find the formula if you happen to need it.

But compare this to mathematical ideas that everyone truly needs, and that are not taught in high school, at least not on a regular basis. Take the basic ideas of statistics, in particular the idea of sampling and the often-abused idea of "statistical significance." These concepts are essential to all citizens because they enable a person to evaluate the (frequently false) claims made in the media about medical research, public opinion polls, and much else. (For a recent account of the misleading nature of scientific reporting -- in the absence of an understanding of the basic ides of statistics -- see the important article by Jonah Lehrer in the New Yorker of December 13, 2010.)

Here is one more example of the mindlessness of the current crop of "educational reformers" who preach the gospel of testing, large classes, charter schools, firing of teachers, and. overall, a disregard of Dewey's concern for "the child and the curriculum." See my previous posting here.