Estimating Teacher Contributions to Student Learning: The Role of the School Component
Teachers’ individual contributions to student learning and schools’ contributions are typically intertwined. This paper explores the key issues related to strategies for identifying a value-added model to account for school and teacher contributions that create appropriate incentives for teachers.
The authors make the following conclusions:
- Differences in teacher value-added scores between schools are generally small in comparison to within-school differences.
- Ignoring between-school differences (estimating a model without this component) attributes whatever between-school differences do exist to individual teachers.
- A different solution is to estimate between-school differences and then consider what part of those differences should be attributed to teachers. Teachers both are made better by the schools they are in and contribute to the betterment of their schools.
- A decision about how much of between-school differences (school component) to include in a teacher score has an important effect on the rankings of the teachers.
- Whether and how between-school differences are attributed to teachers depends on the intended use of value-added scores and the comparisons among teachers that policymakers wish to make.