This study is the first to exploit policy variation within the same state to examine the effects of school accountability on tacher job changes. Using student-level data from Florida State the authors measure the degree to which schools and teachers were "surprised" by the change in the school grading system (in summer of 2002)— what they refer to as an "accountability shock"— by observing the mobility decisions of teachers in the years before and after the school grading change. They find over half of all schools in the state experience an accountability "shock" due to this grading change. Also, teachers are more likely to leave schools facing increased accountability pressure— and even more likely to leave schools shocked downward to a grade of "F". They are less likely to leave schools facing decreased accountability pressure. Moreover, schools facing increased pressure experience an increase in the quality of teachers who leave or stay and schools with no accontability shock experience no significant change to the quality of teachers that leave or stay.