Andrew Leigh

In the NYT, Nick Kristof writes up an important new paper on the impact of great teachers.

Having a good fourth-grade teacher makes a student 1.25 percent more likely to go to college, the research suggests, and 1.25 percent less likely to get pregnant as a teenager. Each of the students will go on as an adult to earn, on average, $25,000 more over a lifetime — or about $700,000 in gains for an average size class — all attributable to that ace teacher back in the fourth grade. That’s right: A great teacher is worth hundreds of thousands of dollars to each year’s students, just in the extra income they will earn. ...

Conversely, a very poor teacher has the same effect as a pupil missing 40 percent of the school year. We don’t allow that kind of truancy, so it’s not clear why we should put up with such poor teaching. In fact, the study shows that parents should pay a bad teacher $100,000 to retire (assuming the replacement is of average quality) because a weak teacher holds children back so much.

Here's the academic abstract:

The Long-Term Impacts of Teachers: Teacher Value-Added and Student Outcomes in Adulthood
Raj Chetty, John N. Friedman, Jonah E. Rockoff

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 students’ lifetime income by more than $250,000 for the average classroom in our sample. We conclude that good teachers create substantial economic value and that test score impacts are helpful in identifying such teachers.