Good teaching consists of intelligently applying basic principles to particular situations, which are themselves understood by subjective criteria. It isn't hard to differentiate a good teacher from a bad one, once you take time to look, though it does sometimes take some imagination and observation.
The tests are efforts to identify good teaching on a general and objective basis. That's probably doomed to fail from the start, and what theoretical potential is available is quickly crushed by the political components of the process.
The real question is why we need general and objective measures in the first place. The answers have nothing to do with education, and everything to do with the governance of educational institutions. That governance is the real problem, and nothing's going to matter until it's addressed.
The tests are efforts to identify good teaching on a general and objective basis. That's probably doomed to fail from the start, and what theoretical potential is available is quickly crushed by the political components of the process.
The real question is why we need general and objective measures in the first place. The answers have nothing to do with education, and everything to do with the governance of educational institutions. That governance is the real problem, and nothing's going to matter until it's addressed.