You're right of course, metrics invariably improve for exactly the things that are tested. In fact, that's exactly the problem. They increase far out of proport

You're right of course, metrics invariably improve for exactly the things that are tested. In fact, that's exactly the problem. They increase far out of proportion with their actual educational value, leaving behind everything else. ie: it's the things that aren't tested (and in many cases aren't testable at all) that are the problem. Think about it this way: all humans are different. We have short ones, tall ones, fat ones thin ones. Some can run a marathon almost without trying while for others it would nearly kill them. So everyone is different, and for kids especially they are different not just because their final state will be different but because they follow dramatically different paths developmentally. Teaching is an art form, a fine skill or understanding and nurturing each student along their unique path to realize the best outcome for each child. Standardized testing is like a club to this: it smashes down on children and insists they and their teachers follow one defined path that is almost completely inappropriate for many children. It actively interferes with a teacher's ability to tailor an educational path for a child. For example, if a child is not ready to learn a particular level of math, force feeding them a higher level is almost certainly counter productive and will have highly negative consequences. Yet that is what the standardized test encourages (even demands, once things like salaries and funding get linked to the results).