voiceofsandiego.org: Schooled... Blogger for a Day: Holding a Lighted Match Under the Thermostat:
"To use another analogy, merit pay is like holding a lighted match under the thermostat in order to claim that the temperature of the room is rising. If the current testing regime becomes even more 'high stakes' for teachers, they will certainly seek out teaching assignments in schools where students are the most likely to score high on tests or to show improvements in test scores from year to year. This means that teachers will avoid schools with the student populations who are most in need of high quality instructors."
"To use another analogy, merit pay is like holding a lighted match under the thermostat in order to claim that the temperature of the room is rising. If the current testing regime becomes even more 'high stakes' for teachers, they will certainly seek out teaching assignments in schools where students are the most likely to score high on tests or to show improvements in test scores from year to year. This means that teachers will avoid schools with the student populations who are most in need of high quality instructors."