Comparing Between-Teacher Variance Estimates From the Value-Added Modeling Literature

• In Event: Issues in Value-Added Models for Teacher Accountability

Abstract

Use of value-added modeling (VAM) in accountability contexts raises a fundamental and controversial issue: how much of the variability in test scores can be attributed to differences between teachers? The proposed paper will describe and compare between-teacher variance estimates for U. S. elementary teachers, with particular attention to the following research questions: 1) Are there systematic differences between estimates obtained using different model specifications? 2) Are there systematic differences between estimates from math and reading test scores? 3) What do meta-analysis techniques reveal about the range and homogeneity of the estimates?

Author

• Kellie Wills, National Institute for Excellence in Teaching