> They also help, by identifying bad teachers and bad schools.
Aside from the arguments posted in sibling comments about what's being measured, you also have a problem of unaligned incentives. In particular, your claim only has a chance of being true if the students are actually interested in scoring as high as they can on the exam. Even at the AP level (I teach at university level and interact with secondary teachers that teach smart, high-level students taking CS), there are students who have decided that they don't care about the subject, or maybe even like the subject but have no (perceived) benefit from a high score due to their chosen college not giving credit in that subject or whatever. Such students may leave their answer book blank, or doodle in it, or maybe just blast through for the easy points and finish early and not worry about thinking about it.
This isn't even necessarily a particularly irrational choice on their part!
But it's a strong argument why the exams shouldn't be used to evaluate the teacher or the school. In a lot of places the students aren't permitted to opt out of the exam, even if they don't care about it, but there's no penalty to the student for taking a dive on it (and any penalty you could try to assess would have false positives and false negatives and still not motivate many of the students with differently-aligned incentives).
All of these problems are going to be a million times worse on a general-education primary- or secondary-level assessment than they are on AP exams.
Aside from the arguments posted in sibling comments about what's being measured, you also have a problem of unaligned incentives. In particular, your claim only has a chance of being true if the students are actually interested in scoring as high as they can on the exam. Even at the AP level (I teach at university level and interact with secondary teachers that teach smart, high-level students taking CS), there are students who have decided that they don't care about the subject, or maybe even like the subject but have no (perceived) benefit from a high score due to their chosen college not giving credit in that subject or whatever. Such students may leave their answer book blank, or doodle in it, or maybe just blast through for the easy points and finish early and not worry about thinking about it.
This isn't even necessarily a particularly irrational choice on their part!
But it's a strong argument why the exams shouldn't be used to evaluate the teacher or the school. In a lot of places the students aren't permitted to opt out of the exam, even if they don't care about it, but there's no penalty to the student for taking a dive on it (and any penalty you could try to assess would have false positives and false negatives and still not motivate many of the students with differently-aligned incentives).
All of these problems are going to be a million times worse on a general-education primary- or secondary-level assessment than they are on AP exams.