Two new studies add to the growing body of peer effects research that confirms what seems self-evident: learning alongside motivated, smart students enhances student outcomes. The first examines the peer effect on pre-K students diagnosed with a disability. Researchers measured student achievement among 670 students, roughly half with an IEP, in eighty-three classrooms in one Midwestern state, using teacher ratings of students’ language ability gains between the fall and spring of a single school year. IEP students appear apt to languish, language-wise, if enrolled in a low-skilled classroom; they do better when mainstreamed into heterogeneous settings. The second study uses Philadelphia public-schools data on nearly 35,000 elementary-school students who took the Stanford 9 exams during the mid- to late 1990s. The analyst employs a few different empirical strategies to untangle the true peer effect from other confounding factors. The main finding: elementary-school students in this urban district gained significantly when learning in a classroom with high-achieving peers, compared to similar students in an average classroom. The converse also applies. Students lost ground when placed in classrooms of lower average achievement. Interestingly, achievement also significantly increased in classrooms with more girls, even if the girls weren’t higher achieving. Predictably, achievement sank in classrooms containing more children with behavioral problems. As the proverb goes, iron sharpens iron—the research indicates that children stand to benefit when learning with suitable peers. Yet, as Daniel Willingham points out, it’s unclear whether enough well-mannered, high-aptitude students exist for all their peers who might benefit from sitting alongside them in class. Hence, designing optimal classrooms within the constraints of a school’s student body remains something of an engineering problem and a moral dilemma.
SOURCES: Laura M. Justice, et al., “Peer Effects in Early Childhood Education: Testing the Assumptions of Special-Education Inclusion,” Psychological Science (2014): 1-8; Michael A. Gottfried, “Peer Effects in Urban Schools: Assessing the Impact of Classroom Composition on Student Achievement,” Education Policy 28 (2014): 607-647.
