The Long-Term Impacts of Teachers: Teacher Value-Added and Student Outcomes in Adulthood
Are teachers' impacts on students' test scores ("value-added") a good measure of their quality? This question has sparked debate largely because of disagreement about (1) whether value-added (VA) provides unbiased estimates of teachers' impacts on student achievement and (2) whether high-VA teachers improve students' long-term outcomes. We address these two issues by analyzing school district data from grades 3-8 for 2.5 million children linked to tax records on parent characteristics and adult outcomes. We find no evidence of bias in VA estimates using previously unobserved parent characteristics and a quasi-experimental research design based on changes in teaching staff. Students assigned to high-VA teachers are more likely to attend college, attend higher- ranked colleges, earn higher salaries, live in higher SES neighborhoods, and save more for retirement. They are also less likely to have children as teenagers. Teachers have large impacts in all grades from 4 to 8. On average, a one standard deviation improvement in teacher VA in a single grade raises earnings by about 1% at age 28. Replacing a teacher whose VA is in the bottom 5% with an average teacher would increase the present value of students' lifetime income by more than $250,000 for the average class- room in our sample. We conclude that good teachers create substantial economic value and that test score impacts are helpful in identifying such teachers.
We thank Joseph Altonji, Josh Angrist, David Card, Gary Chamberlain, David Deming, Caroline Hoxby, Guido Imbens, Brian Jacob, Thomas Kane, Lawrence Katz, Adam Looney, Phil Oreopoulos, Jesse Rothstein, Douglas Staiger, Danny Yagan, and seminar participants at the NBER Summer Institute, Stanford, Princeton, Harvard, Univ. of Chicago, Univ. of Pennsylvania, Brookings, Columbia, Univ. of Maryland, Pompeu Fabra, University College London, Univ. of British Columbia, and UC San Diego for helpful discussions and comments. This paper draws upon results from a paper in the IRS Statistics of Income Paper Series entitled "New Evidence on the Long- Term Impacts of Tax Credits on Earnings." Tax microdata were not accessed to write the present paper, as all results using tax data are based on tables contained in the SOI white paper. Peter Ganong, Sarah Griffis, Michal Kolesar, Jessica Laird, and Heather Sarsons provided outstanding research assistance. Financial support from the Lab for Economic Applications and Policy at Harvard and the National Science Foundation is gratefully acknowledged. The views expressed herein are those of the authors and do not necessarily reflect the views of the National Bureau of Economic Research. Publicly available portions of the analysis code are posted at: http://obs.rc.fas.harvard.edu/chetty/va_bias_code.zip
Chetty, Raj, John N. Friedman, and Jonah E. Rockoff. 2014. "Measuring the Impacts of Teachers I: Evaluating Bias in Teacher Value-Added Estimates." American Economic Review, 104(9): 2593-2632.