Pay for Performance

Colleagues in the US who may have already suffered through this hare-brained scheme, we are about to suffer the same through the same system. Like nearly all policies implemented by our current government it appears to have had little thought put into the 'how'. Will some agency be created to actually think this through that has the students' interests at heart? I don't think so! I though economic rationalism was going to leave education, seems it will be with us for another decade at least. What do others think about pay for performance in education?