Traditional teacher evaluation systems have come under scrutiny for failing to meet two objectives of personnel evaluation: improving teacher’s instructional practice and identifying and removing low-performing teachers from the classroom. In this paper, we provide new evidence on the role of evidence-based evaluation systems in accomplishing the second goal – removing low-performing teachers.  We explore a pilot teacher evaluation system in Chicago Public Schools (CPS) – The Excellence in Teaching Project (EITP) – and the extent to which the introduction of this dramatically new evaluation system impacted teacher turnover.

The EITP pilot, introduced in 44 randomly selected elementary schools in 2008-09 (Cohort 1) and then scaled up to include an additional 48 schools (Cohort 2) in 2009-10, focused on the classroom observation component of teacher evaluation and used Charlotte Danielson’s Framework for Teaching (FFT) to guide principals’ observations of and conferences with teachers. We explore the extent to which the introduction of a dramatically new teacher evaluation system in Chicago impacted teacher turnover in the district, and consider two margins of turnover – teacher exit from the district (the extensive margin) and teacher transfer to other schools within the district (the intensive margin). While the impact of the new teacher evaluation system on the extensive margin may be considered a goal of a system aimed at removing underperforming teachers from the district’s labor market pool, policymakers should also be concerned with whether such a system leads to a reallocation of teacher quality through teacher transfers across schools within the district, a potentially unintended consequence of newly-developed teacher evaluation systems.

Leveraging the experimental design of the pilot’s rollout, we find that teachers who had low prior evaluation ratings (Unsatisfactory or Satisfactory) were more likely to leave the district because of the evaluation pilot. In the control schools, 13.5 percent of low-rated teachers left the district at the end of the 2008-09 school year, compared to 25.8 percent of low-rated teachers in treatment schools after the first year of implementation. This represents a 91 percent increase in the turnover of the lowest-performing teachers, providing evidence that teacher evaluation reform has the potential to impact the distribution of teacher quality. We also find that non-tenured teachers, who have few contractual protections in terms of job security, were significantly more likely to leave the district after one year of implementation. Among non-tenured teachers, we find a 46 percent increase in turnover rates. We do not find that teachers are more likely to transfer across schools within the district after implementation of the pilot, nor do we find that teachers disproportionately leave schools that vary on the achievement level of their students or serve differing shares of students receiving free/reduced-price lunch. These findings suggest that evidence-based evaluation systems have the potential to identify low-performing teachers by providing better informational signals about teacher quality while also inducing these teachers to exit the district.