How Does Desegregation Help Reduce the Achievement Gap?

August 15, 2010

Jane Cooley

Jane Cooley

Desegregating schools has long been considered a matter of equity, justice, and improved student achievement.

But there is still a lot to learn about exactly how having diverse classrooms improves student achievement. For example, do student peer groups affect individual achievement?

Yes, peer effects are important determinants of student achievement, but it remains difficult to calculate the actual effects of desegregation directly.  WCER researcher Jane Cooley uses a new approach to identify the effect of peer behavior on individual student achievement.

Studying a group of public elementary school students in North Carolina, Cooley found that

  1. Peer group effects exist primarily within race-based reference groups,
  2. Their influence diminishes across range of student achievement, and
  3. Desegregating peer groups narrows the achievement gap only marginally, on average, but this average masks important gains for lower achievers.

Cooley measures specific effects of desegregation by separating the effects of teacher quality from those of student peer group composition.  She says students appear to form race-based reference groups within classrooms. White students conform to white peer achievement and nonwhites conform to nonwhite peers. To date, research has not explored this type of heterogeneity, yet it has important implications for understanding the effect of desegregation.

Cooley finds that peer group effects are stronger within race than across races. At the same time, lower-achieving students benefit relatively more than higher achievers from increases in average peer achievement. In other words, the within-race effects diminish across the range of student achievement.

Previous studies have not determined the effects from contemporaneous achievement of peers of the same race. But Cooley finds that these effects play a central role in determining the achievement benefits associated with creating racially diverse classrooms.

Cooley’s study found a lack of cross-racial effects. Such a lack would limit the benefits of desegregation. For example, nonwhites would experience gains in achievement if grouped with higher achieving nonwhite peers on average, and whites would experience losses if grouped with lower-achieving white peers on average. Furthermore, given that lower-achieving students benefit relatively more than higher-achieving students, we might expect efficiency gains in terms of increases in average achievement, to the extent that desegregation also creates more mixed-ability classrooms.

A higher concentration of nonwhites is negatively correlated with achievement. This suggests that creating more diverse peer groups would raise nonwhite achievement while having little effect on white achievement.

Cooley’s findings suggest that previous studies have severely understated the effect of peers. That’s because those studies have overlooked behavioral effects deriving through contemporaneous achievement gains.  
See WCER Working Paper 2010-3.