The Value Added Teacher Model Sucks
Today I want you to read this post (hat tip Jordan Ellenberg) written by Gary Rubinstein, which is the post I would have written if I’d had time and had known that they released the actual Value-added Model scores to the public in machine readable format here.
If you’re a total lazy-ass and can’t get yourself to click on that link, here’s a sound bite takeaway: a scatter plot of scores for the same teacher, in the same year, teaching the same subject to kids in different grades. So, for example, a teacher might teach math to 6th graders and to 7th graders and get two different scores; how different are those scores? Here’s how different:
Yeah, so basically random. In fact a correlation of 24%. This is an embarrassment, people, and we cannot let this be how we decide whether a teacher gets tenure or how shamed a person gets in a newspaper article.
Just imagine if you got publicly humiliated by a model with that kind of noise which was purportedly evaluating your work, which you had no view into and thus you couldn’t argue against.
I’d love to get a meeting with Bloomberg and show him this scatter plot. I might also ask him why, if his administration is indeed so excited about “transparency,” do they release the scores but not the model itself, and why they refuse to release police reports at all.