The moment you tie income to results, you incentivize teachers leaving behind students who won't perform.
The moment you tie income to results, you incentivize teachers leaving behind students who won't perform.
Could you pay more to attract better teachers in that situation and get better overall value for the kids being taught?
So how do you identify poor teachers? I would guess that if you let each member of the faculty vote for the 25 top teachers and then have parents do assessment of their children's teachers and then average the results over 3 years, you could come up with something that has virtual no false positives as to who the worst teachers were.
I agree with the ensemble of evaluations approach - student tests at the start and end of year show student attainment, student and parent feedback, peer feedback, and administrator feedback. Come up with a weighted average and experiment with it. Retain average and better teachers, reward rockstars, train underperformers, and let the bottom ranks and those who don't improve with training go.
An average sounds like a shitty, shitty system. Imagine finding out your kid is in a classroom with every low-performing and difficult kid in the grade just because it was random.