If my school does poorly, I get nailed on my evaluation. It's not a big deal at my school because we do pretty well. But across town and in districts across the state, it's a huge issue. The last few years have seen controversies over school scores and turnover at those low-SES schools. Gee, sign me right up, thanks.
Schools get more money if their scores are good.
Principals get more money if their scores are good. But there's a huge incentive to teach to the test. Another problem is special education. Many are legitimate, some are done to help the school's score. Many districts are being audited by the state to make sure spec ed kids belong there and aren't just exempt for TAAS purposes.