This Incredibly Powerful Chart Shows How Much Of A Difference A Good Teacher Can Make
Skeptical that good teachers really make a difference in their students lives? Don't be.
Better teachers, measured by how much they boost student test scores, significantly raise adult earning potential.
Replacing a teacher in the bottom 5% with an average one will boost a student's estimated lifetime income by $250,000.
Having a great teacher, one that's a standard deviation (SD) better than the median for one grade boosts a student's income at age 28 by an average of 1.3%
This according to a new series of working papers (I and II) from John Bates Clark medal winner Raj Chetty, and coauthors Jonah Rockoff and John Friedman. They find primary school students who had better teachers are more likely to go to college, go to better schools, earn more money, and are less likely to have children as teenagers.
Here's the author's chart outlining the impact of teacher quality on adult earnings, which rises over time:
Figuring out how to measure teacher quality is controversial. Right now, places like Los Angeles and Washington, D.C. are just starting to measure teachers by value added metrics (VA), the amount that they boost test scores.
The first paper in the series finds that the ability to boost test scores is a useful measure of teacher quality, that differences in scores come from teacher ability, not student sorting. Eighty-five percent of differences in VA are within schools, not between them. It might be worth considering more broadly.
