Thursday, March 14, 2013

Jersey Jazzman: NJ Teacher Evaluation: Math Fail #1

Jersey Jazzman: NJ Teacher Evaluation: Math Fail #1:


NJ Teacher Evaluation: Math Fail #1

Do the Broad-funded interns at the New Jersey Department of Education understand math?

I ask because their disastrous teacher evaluation proposals, announced with great fanfare last week, betray an embarrassing misunderstanding of the fundamentals of mathematics. It will take a few posts to catalog them all, but let's start with this:

A large portion of a "tested" teacher's evaluation will now include a metric called a "Median Student Growth Percentile," or mSGP. In a previous post, I showed how SGPs are woefully inappropriate for use in teacher evaluation, because they are purely descriptive measures: they do not measure how a teacher contributes to student learning.

But even if we put aside the problems of SGPs, there are still obvious problems with mSGPs; obvious, that is, to anyone with a basic understanding of the difference between a median and a mean.