Wednesday, January 9, 2013

Jersey Jazzman: Rhee's Phony Math

Jersey Jazzman: Rhee's Phony Math:


Rhee's Phony Math

So the edu-blogosphere has lit into the StudentsFirst "report card" - and rightly so. Aside from the fact that SF doesn't rate states by their students' achievement level - and isn't that the entire point of Rhee-form anyway? - the categories and rubrics Michelle Rhee's outfit came up with are absurd. G.F. Brandenburg, who knows Rhee as well as anyone, takes a good look at how subjective and inane SF's criteria are.

But even if SF had rational and relevant benchmarks for ranking states, the "report card" would still be utterly phony, because it's based on faulty math. Here's p.66 of the report, which explains SF's methodology:

No. No, no, no. Sweet lord, no.

Folks, it is a basic precept of mathematics that you must round averages to the correct significant figure. You are not allowed to express an average in any more digits than the original data, because you run the risk of