It is fair to reward teachers on the actual results they achieve.  Just as in the private sector, workers should be judged and rewarded on the actual results they achieve. Whether it's through sheer talent or through hard work, some teachers consistently deliver better results than other teachers. Those teachers are more effective and efficient at providing societal value: with the same amount of work-hours they manage to more effectively educate children. It is therefore only just that their pay is differentiated according to the results they achieve.