Why merit pay for teachers doesn't work

I see that our Minister of education has trotted out the old mantra that merit pay for teachers will improve education by rewarding better teachers.

Well maybe she hasn't read this (or ANY of the research on the issue), or maybe her officials haven't, or maybe they just don't want to??

Here is an excellent summary from the Washington Post.

It seems that merit pay often isn't the best way to motivate better performance .. well there's a surprise.