Bad bad bad. There are just too many variables in each classroom to be able to determine whether a teacher is good based solely on test scores- and that is how they would do it. If I have a classroom of regular and special education students, and my colleague has only honors classes, would it be fair that she gets more pay because her students would inevitably score higher on tests? Also, I may be the best teacher in the world, but if I have a student who misses 50% of classes and does nothing to make that work up, and whose parents clearly don't care whether she gets an education, what can I do? Is it fair that her test scores will determine my pay? I don't think so. Policy makers are trying to turn education into a business. Well, businesses can choose their employees based on who will give them success. I can't choose my students. I want every student to have a fair shot and I will do my best to teach each student regardless of what I am getting paid, but I think the idea of merit pay is absolutely ludicrous.