I'm interested to see what the fallout of this will be. Will other towns crunch the same data?
From Alex Tabarraok's commentary from the link:
I don't blame the unions for being up in arms and I feel for the teachers, for some of them this is going to be a shock and an embarrassment. We cannot simultaneously claim, however, that teachers are vitally important for the future of our children and also that their effectiveness should not be measured. As systems like this become more common students will benefit enormously and so will teachers.
They are already finding a few "Beloved Teacher Mrs. X"s who are ending up in the bottom 10%. But, we're told, that's okay, because they teach valuable "critical thinking" skills that are not measured on the tests.