45 Pages Posted: 28 Jun 2017
Date Written: June 20, 2017
At least sixteen US states have begun to hold teacher preparation programs (TPPs) accountable for teacher value-added to student test scores. Yet it is unclear whether the teacher quality differences between TPPs are large enough to make an accountability system worthwhile. We reanalyze the results of peer-reviewed TPPs evaluations in 6 states: New York, Louisiana, Missouri, Washington, Texas, and Florida. Our results show that teacher quality differences between most TPPs are negligible—0-0.04 standard deviations in student test scores—even in states where larger differences were reported originally. We can single out about one TPP per state that differs significantly from the average in one tested subject. Several statistical practices can exaggerate apparent differences between TPPs, including underestimation of standard errors (SEs), display of narrow confidence intervals that extend only one SE in each direction, failure to correct for multiple comparisons among the 10-100 TPPs in each state, underappreciation of how noise affects the distribution of TPP estimates, and confounding of between-TPP variance with variance in the comparison group.
Keywords: accountability, heterogeneity, teacher training
JEL Classification: I21, I28, C1
Suggested Citation: Suggested Citation
von Hippel, Paul T. and Bellows, Laura, How Much Does Teacher Quality Vary Across Teacher Preparation Programs? Reanalyzing Estimates from 6 States (June 20, 2017). Available at SSRN: https://ssrn.com/abstract=2990498