"This paper presents the first causal evidence on the effects of school accountability systems on teacher labor markets. We exploit a 2002 change in Florida's school accountability system that exogenously shocked some schools to higher accountability grades and others to lower accountability grades, and measure whether teachers in shocked schools are more or less likely to move. Using microdata from the universe of Florida public school teachers, we find strong evidence that accountability shocks influence the teacher labor market; specifically, teachers are more likely to leave schools that have been downward shocked -- especially to the bottom grade -- and they are less likely to leave schools that have been upward shocked. We also find that accountability shocks influence the distribution of the measured quality of teachers (in terms of value added measures) who stay and leave their school, though the average differences are not large"--National Bureau of Economic Research web site.