Performance pay does not make it easier to dismiss poor teachers. A temporary work contract will. If heads made use of the sensible probationary period of two years when a teacher first starts at the school, and actually fired underperforming teachers, then we wouldn't have the problem of poor teachers moving up the pay scale at the same rate as good teachers. They wouldn't be moving up the pay scale at all: they'd be out of a job. 

Performance pay is really meant to do two things: reward good teachers, and encourage teachers who are stagnating to work harder and better. 

Teachers who are not performing do so for one of two reasons, or sometimes both. Either they are lazy and cannot be bothered, or they are genuinely struggling under the demands of the job. Do we really think that by putting an extra £500 carrot in front of the lazy teachers that they are suddenly going to become outstanding? If they aren't already motivated by the children they teach, money isn't going to help. If they're so bad, then they should be fired. Simple. 

What of the struggling teacher? She loves her kids, but she is new at the job and is taking time to get to grips with being a good teacher. She's under a lot of stress, and sometimes cries in bed at night when she finally gets there after finishing her lesson plans at 2am. Does it make sense to demoralise this teacher by dangling £500 in front of her and then take it away? Let's be clear: there is nothing she could do differently (in a practical sense) that might have earned that £500. Now she'll resent the fact that you aren't giving it to her. This teacher who, given another year in the job, might have blossomed and stayed, giving much needed consistency and order to your school, leaves in disappointment and anger, all for the sake of £500.

Schools are not like businesses. Consistency means everything to a school. The bond between pupil and teacher is crucial, and the greater the number of years teachers have been at a school, the better the learning experience for pupils. 

Does PRP reward good teachers? Yes. Or at least, it rewards those teachers who appear to be good. Performance-related pay is all well and good as long as you can measure performance. Any measure needs to be valid, reliable and considered fair and accurate by the teachers themselves, or you'll create an unhappy atmosphere in the school that will drive teachers away. Let's look at the issues.

1. Teachers work as a team. A head of department might support less experienced teachers by taking the more challenging children into her class. Head and teacher share resources. They achieve common whole-school goals through co-operating. Establish a culture of every man for himself, where that head of department may very well lose out on her £500 if she takes in challenging kids, and she'll stop helping the weaker staff. Her results won't be as good if she has more challenging kids. There isn't any way of measuring the exact effect. If only there were. But teaching is not a science; it's an art-you don't always get the same output from the same input. Children are not predictable, and classes even less so. Remove one or two miscreants from a troublesome class and it can be transformed into a team of high-achievers.