Harvard logo THE LONG-TERM IMPACTS OF TEACHERS  Columbia Business School
Raj Chetty
Harvard University
  John N. Friedman
Harvard University
  Jonah E. Rockoff
Columbia University



   » Executive Summary

   » Complete Paper
        Part 1: Bias in VA Estimates
        Part 2: Long-Term Impacts

   » NBER WP 17699 [old version]         

   » Education Next article         

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   » Presentation Slides [PPT] [PDF]

   » STATA Code

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A teacher's "value-added" is defined as the average test-score gain for his or her students, adjusted for differences across classrooms in student characteristics (such as their previous scores).
Is teacher value-added a good measure of teacher quality?  

When a high value-added (top 5%) teacher enters a school, end-of-school-year test scores in the grade he or she teaches rise immediately...

... and students assigned to such high value-added teachers are more likely to go to college, earn higher incomes, and less likely to be teenage mothers. On average, having such a teacher for one year raises a child's cumulative lifetime income by $80,000 (equivalent to $14,500 in present value at age 12 with a 5% interest rate).

The earnings gains from replacing a low value-added (bottom 5%) teacher with one of average quality grow as more data are used to estimate value-added. Discounting future earnings gains to present value, the gains are $270,000 with 3 years of data. If future earnings are not discounted, cumulative earnings gains surpass $1.4 million per class.

We conclude that great teachers create great value, and that test-score based value-added measures are one useful input into identifying such teachers.


Note: The results of this study were originally disseminated as NBER WP 17699. The study has since been revised and divided into two separate manuscripts. The first manuscript evaluates bias in VA estimates, while the second identifies teachers' long-term impacts. The two final manuscripts as well as the original paper are posted on this site; the STATA code corresponds to the revised manuscripts.



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