The teaching launch

It’s often said that a good teacher can change a student’s life, and now a Harvard researcher is demonstrating how much influence an effective educator can have.

As described in a study in the Oct. 7 Proceedings of the National Academy of Sciences, Gary Chamberlain, the Louis Berkman Professor of Economics, found that middle school teachers can have an impact not only on students’ short-term educations, but on whether they attend college, and on the size of their paychecks at age 28.

“This study definitely offers suggestive evidence, certainly in a predictive sense, that teacher quality matters,” Chamberlain said. “What we’re trying to do is put numbers on the variation in teacher quality and how large an effect it has on test score outcomes, and later outcomes, like college attendance and income.”

How big is the impact teachers can make? When it comes to whether a student will attend college, Chamberlain said, the size of the effect depends on how teacher quality is measured. If teacher quality is measured solely in terms of test scores, the effect is rather small. Increasing teacher quality from the 50th to the 84th percentile resulted in an increase in college attendance of just 0.13 percent.

But when teacher quality was measured by examining the number of students who had a particular teacher and later attended college, the effect was dramatically higher. An increase in teacher quality produced a nearly 1 percent increase in college attendance.

“On average, about 38 percent of the students in this data set went on to college, so to go from 38 to nearly 39 percent, that actually is a big deal,” Chamberlain said.

In the case of earnings, the data showed students who had better teachers earned about $200 more per year, an increase of about 1 percent.

Chamberlain warned that there were factors the study was unable to control for, so influences beyond teacher quality may be contributing to the effect. While the data on college attendance could control for income variations among parents, it did not take into account parents’ education, Chamberlain said. A similar uncertainty existed for the income measures, where the standard error was nearly $95.

“For years, there has been a strong sense that teachers matter,” Chamberlain said. “This study shows that there are teacher characteristics that matter, but we need more and better data to identify what those characteristics are. Fortunately, there are researchers here, and groups like the [Bill & Melinda] Gates Foundation, that are working to gather that data and understand what those characteristics are.”