We use statewide data from Massachusetts to investigate teacher performance evaluations as a measure of teaching effectiveness. Consistent with prior research, we find that assignment to lower achieving classrooms reduces teachers’ performance ratings. But after adjusting for these and other observable differences between classroom assignments, we show that regression-adjusted performance measures can reliably predict future evaluation ratings as teachers move across grades and subjects within the same school. However, we also document substantial unexplained variation in ratings across schools and districts in the state. In particular, districts vary substantially both in the extent to which they differentiate between teachers and in the sensitivity of performance ratings to differences in teacher effectiveness as measured by value added. As a result, even after regression adjustment, teacher evaluation ratings generally provide unreliable predictions of future teacher evaluations after teachers switch schools. These findings suggest that policymakers and researchers should use caution in using performance evaluation ratings to make comparisons between teachers in different contexts.

WP 197-0618-1 was originally released in June 2018. An updated version (WP 197-0618-2) was released in August 2020.

This paper has been published in the Journal of Research on Educational Effectivess and can be found here, March 2022.