As policymakers focus on identifying and rewarding effective teaching, they should pay close attention to an important new study demonstrating the powerful effect of teacher collaboration in producing greater student achievement gains.
Using 11 years of student data in North Carolina, researchers have found that most value-added achievement gains are attributed to the make-up of teacher teams, not the traits and characteristics of individual teachers. Drawing on sophisticated analyses of this large database, they reported in a paper published by the National Bureau of Economic Research that peer learning among small groups of teachers seems to be the most powerful predictor of student achievement over time.
Researchers C. Kirabo Jackson and Elias Bruegmann found that "students have larger test score gains when their teachers experience improvements in the observable characteristics of their colleagues." Less experienced teachers who are still acquiring “on-the-job” skills are most sensitive to changes in peer quality; teachers with greater labor-market attachment are more sensitive to peer quality; and both current and historical peer quality changes affect current student achievement.
The researchers warn that using value-added methods to identify individual teachers for merit pay and other high stakes decisions may very well be confounded by how teachers learn from each other. As one of the study’s authors noted, “If you give the reward at the individual level, all of a sudden my peers are no longer my colleagues—they’re my competitors. If you give it at the school level, then you’re going to foster feelings of team membership, and that increases the incentive to work together and help each other out.”
It is time to figure out 21st century teaching effectiveness systems that both identify expert teachers and reward them for spreading their expertise to others. I've been harping on the importance of this "spread effect" for some time. It's exciting to see research from a disinterested source that substantiates this key component of effective teaching.