I don't think tying pay bonuses to standardized test scores alone is the best way to go, and I acknowledge that figuring out where one teacher's contribution to student learning may end and another's may begin, making the whole idea of merit bonuses tricky, take a look what the always-helpful teacher's union president has said on the issue in the past:
The UFT president, Randi Weingarten, has said in the past that using test scores to set salaries or determine tenure is like "telling an oncologist that the only way to keep your job is for your cancer patients to survive." A spokesman for the union said Ms. Weingarten had no comment on the grant.
Er...no, Randi. That's not a good comparison at all, and how happy you must be that the analogy section of the SAT has been dispensed with forever. However, I would be willing to bet that oncologists who do have a good track record of patient survival tend to be more in demand than those who don't, and get paid quite a bit better. Just a guess.
Is there some reason I haven't figured out why teachers should be the only employed adults for whom compensation must never be tied, in any way, to competent performance?