Teacher compensation is another bone of contention. Currently the vast majority of teachers have salaries determined by seniority. There are increasing movements  to make salaries more merit-based. This presents the difficulty of determining what standard of merit should be used for these judgements. The need for some way of measuring students' ability is something that the No Child Left Behind act is attempting to address. Other interested parties may have proposed other metrics.
Teacher's unions, often very powerful politically, have consistently opposed the implementation of merit-based pay systems for teachers. They have killed propositions in California and other systems by using their substantial political clout and portraying such measures as 'anti-education'. One has to wonder if students would agree.
Most other fields of employment are compensated on a combination of seniority and merit, weighted toward merit, and there is no reason why education should be any different.