The teacher's pay will be based on testing. This most likely will be standardized testing which already does not work for many children and then the teacher will be compensated poorly, not because of their teaching, but because the system in place already is not working. There are many other ways to document children's learning that should not be by standardized testing.
http://www.examiner.com/x-2157-Charter-Schools-Examiner~y2009m10d25-Gates-Foundation-and-Obama-Administration-unequally-yoked
http://www.swamppolitics.com/news/politics/blog/2009/10/race_to_the_top_teachers_left.html
http://www.ledger-enquirer.com/news/photos/story/885203.html