Nearly everyone has an anecdote about the teacher that made a difference to them: the person who taught iambic pentameter or quadratic equations, but also inspired and imparted wisdom. But does teacher quality really matter, or do we simply have fond memories of our mentors?
The answer to the question may seem obvious — how could the quality of a teacher not be critically important to students? But as education policies target teacher quality, the true effect of having a great teacher, versus a merely average one, has been difficult to assess.
“It’s very plausible that teacher quality matters; there’s nothing very surprising about that,” said Gary Chamberlain, an economist at Harvard University. “But it’s been extremely hard to document for quite a while.”
In a study published in the Proceedings of the National Academy of Sciences , Chamberlain analyzed data from an unidentified large urban school district and found that middle-school teachers could have a small, but real influence on whether people attend college and how much they earn at age 28. His study does not allow him to identify the factors that made one teacher better than another, but instead shows that increasing teacher quality significantly, say from the 50th percentile to the 84th percentile, increases the likelihood a child will attend college by nearly one percentage point. Such an increase also adds to future annual income by nearly $200 — an increase of about 1 percent.
Chamberlain said that’s a powerful effect for just one teacher and one class to have on any child’s future trajectory. But there are many factors at play. For example, in the study, he could not rule out parents’ education levels might help account for the difference.
He said the type of work he does can establish how powerful a good teacher can be, and that knowledge could help focus policies on interventions likely to have the most impact.