Value-Added to What? How a Ceiling in the Testing Instrument Influences Value-Added Estimation
NBER Working Paper No. 14778
Value-added measures of teacher quality may be sensitive to the quantitative properties of the student tests upon which they are based. This paper focuses on the sensitivity of value-added to test-score-ceiling effects. Test-score ceilings are increasingly common in testing instruments across the country as education policy continues to emphasize proficiency-based reform. Encouragingly, we show that over a wide range of test-score-ceiling severity, teachers' value-added estimates are only negligibly influenced by ceiling effects. However, as ceiling conditions approach those found in minimum-competency testing environments, value-added results are significantly altered. We suggest a simple statistical check for ceiling effects.
Published: Cory Koedel & Julian Betts, 2010. "Value Added to What? How a Ceiling in the Testing Instrument Influences Value-Added Estimation," Education Finance and Policy, MIT Press, vol. 5(1), pages 54-81, January.