Ranking attempts tend to go bad and become hellish and/or are abused to get rid of people for personal or political reasons while bypassing normal processes and protections against firing.

I mean, software developers love stack ranking, right? We can go ahead and fire anyone who doesn't close X Jira tickets per month, I'm sure. Lines of code? Business impact? (oh, sorry, that critical bugfix you did doesn't fit in our measurement framework so you're underperforming, have a PIP).

"Wait but we can just measure performance with tests" LOL OK, if you thought "teaching to the test" was bad before...

And anyway they do already measure performance with year-over-year student progress on state tests, and there are consequences if you suck at it for too long. At least around here. There's enough leeway that it's not horrible but it's also not great and does encourage some of those teach-to-the-test behaviors that people claim to hate. A good teacher would 100% for sure teach better not being judged under that system, and it's one of many things that push them out of teaching—even if they do fine on the metrics, it contributes to frustration and job dissatisfaction, having to do less-than-optimal things or else stress about test scores[1]. A bad one, perhaps, is better for being so judged.

[1] Example: several of these kids are effectively two grade levels behind on [subject]. Do I try to fill in those gaps, and leave them with little understanding of the material that will be on this year's test and so nearly certain to miss every question, or do I treat of the earlier material only when absolutely necessary so they see most of this year's stuff (even if understanding it poorly), so score a little higher than they would otherwise? The former is definitely better for the students, but if you get a "low" class you're (the teacher) gonna be fucked on your standardized testing scores if you do that. This is a real, and not uncommon, situation to be in.

You can probably phrase this as "teachers would be" and make the same, realistic point without attracting as much ire? It was my first thought too. Another option would be to have a rotation.