The modernization of teacher evaluation systems, an increasingly common component of school reform efforts, promises to reveal new, systematic information about the performance of individual classroom teachers. Yet while states and districts race to design new systems, most discussion of how the information might be used has focused on traditional human resource-management tasks, namely, hiring, firing, and compensation. By contrast, very little is known about how the availability of new information, or the experience of being evaluated, might change teacher effort and effectiveness.
In the research reported here, we study one approach to teacher evaluation: practice-based assessment that relies on multiple, highly structured classroom observations conducted by experienced peer teachers and administrators. While this approach contrasts starkly with status quo "principal walk-through" styles of class observation, its use is on the rise in new and proposed evaluation systems in which rigorous classroom observation is often combined with other measures, such as teacher value-added based on student test scores.
Proponents of evaluation systems that include high-quality classroom observations point to their potential value for improving instruction (see "Capturing the Dimensions of Effective Teaching," features, page 34). Individualized, specific information about performance is especially scarce in the teaching profession, suggesting that a lack of information on how to improve could be a substantial barrier to individual improvement among teachers. Well-designed evaluation might fill that knowledge gap in several ways. First, teachers could gain information through the formal scoring and feedback routines of an evaluation program. Second, evaluation could encourage teachers to be generally more self-reflective, regardless of the evaluative criteria. Third, the evaluation process could create more opportunities for conversations with other teachers and administrators about effective practices.
In short, there are good reasons to expect that well-designed teacher-evaluation programs could have a direct and lasting effect on individual teacher performance. To our knowledge, however, ours is the first study to test this hypothesis directly. We study a sample of midcareer elementary and middle school teachers in the Cincinnati Public Schools, all of whom were evaluated in a yearlong program, based largely on classroom observation, sometime between the 2003-04 and 2009-10 school years. The specific school year of each teacher's evaluation was determined years earlier by a district planning process. This policy-based assignment of when evaluation occurred permits a quasi-experimental analysis. We compare the achievement of individual teachers' students before, during, and after the teacher's evaluation year.
We find that teachers are more effective at raising student achievement during the school year when they are being evaluated than they were previously, and even more effective in the years after evaluation. A student instructed by a teacher after that teacher has been through the Cincinnati evaluation will score about 11 percent of a standard deviation (4.5 percentile points for a median student) higher in math than a similar student taught by the same teacher before the teacher was evaluated.
Our data do not allow us to identify the exact mechanisms driving these improvements. Nevertheless, the results contrast sharply with the view that the effectiveness of individual teachers is essentially fixed after the first few years on the job. Indeed, we find that postevaluation improvements in performance were largest for teachers whose performance was weakest prior to evaluation, suggesting that rigorous teacher evaluation may offer a new way to think about teacher professional development.
Evaluation in Cincinnati
The data for our analysis come from the Cincinnati Public Schools. …