As I argued in Building a Better Evaluation System, the power of comprehensive teacher evaluation systems lies not only in simply identifying the few ineffective teachers to fire or the few highly effective teachers to reward with increased compensation, but also in improving the performance of all teachers by providing feedback to help them improve their performance. As I argued in the report, focusing teacher evaluations on the continuous improvement of all teachers rather using teacher evaluations for high stakes personnel decision will have a greater impact on student achievement
A recent report published in the most recent edition of Education Next provides strong evidence that this is indeed the case. The researchers found that teachers were more effective at raising student achievement in the year they were being evaluated than the prior year. Furthermore, they found teachers were even more effective in the years following their evaluations. This supports the idea that teacher evaluation systems can have a significant impact on all teachers, not just those on the extreme ends of the effectiveness spectrum.
It is important to point out this report specifically studied mid-career elementary and middle school teachers, which means these gains were not a result of teachers new to the classroom that typically make significant gains in their effectiveness over their first couple of years. The gains made are from teachers that, as previous research has suggested, typically do not increase their effectiveness significantly from year to year.
However, such gains were not simply due to implementing any old teacher evaluation system. In the case of Cincinnati -the district this study was based on- they had instituted a comprehensive teacher evaluation system focused on peer and administrator observations that provided valuable feedback to the teacher being evaluated. It is that feedback that likely enabled teachers to improve their performance after being evaluated. Being told what your strengths are and how to improve upon your weaknesses appeared to be a powerful tool to improving teacher effectiveness for all teachers in the district. However, if Cincinnati had chosen to create a teacher evaluation system for the purpose of identifying the very least and most effective teachers for personnel decisions, the system would have a much narrower impact on student achievement district-wide.
Of course, identifying the very least and most effective teachers is an important outcome of any teacher evaluation system which would impact student achievement. However, focusing on only identifying those teachers for high stakes personnel decisions instead of focusing on the continuous improvement of all teachers will limit the impact a teacher evaluation system would have on student achievement. – Jim Hull