How good are your kids’ teachers? How bad? If you live in the state of New York, the powers that be will go out of their way to keep you from finding out. Superb report in City Journal:

Ever wonder how effective your child’s teacher is? Officials in Albany would rather you didn’t know. At least that’s the lesson one has to take from their refusal to allow data systems to match students to teachers, though doing so would help the state compete for a pot of perhaps hundreds of millions of federal dollars. Narrow political interests stand in the way of improving our schools and easing New York taxpayers’ burdens.
…One such truth is the effectiveness of individual teachers. Data analysis is far from perfect, and no one argues that it should be used in isolation to make employment decisions. But modern techniques can help us distinguish between teachers whose students excel and teachers whose students languish or fail. There’s just one problem with the data revolution: it doesn’t work without data. States must develop data sets that track the individual performance of students over time and match those students to their teachers.
Unfortunately, New York has deliberately refused to take that step. The state already has a sophisticated system for tracking student progress, but it doesn’t allow this statewide data set to match students to their teachers.

Go read every word.