Classmates Matter Theories of Peer Influences and a National Analysis of the Effects of Peer Characteristics on Student Achievement

Minority and low-income students remain highly concentrated in a small number of schools and research suggests that this concentration reduces long-term outcomes for these students. There are various theories, form economics sociology and other disciplines, regarding why this is the case. This study outlines a unifying framework for comparing the various theories and summarizes some of the most rigorous empirical evidence that might help to test them. In addition, I provide new analysis using a new database of student achievement for racial subgroups in 22,000 U.S. schools. The analysis provides upper-bound estimates on the effects that peer characteristics have on student achievement. Consistent with past research, Black and Hispanic students learn more in racially integrated schools, apparently because of income and associated differences that are correlated with race. White students are relatively unaffected by peer characteristics. However, peer influences are complex so that each peer characteristic affects different types of students in different ways. These findings also inform understanding of the validity of the various theories. Acknowledgements: The author gratefully acknowledges funding support from the Center for American Progress, data assistance from the American Institutes for Research, and helpful comments from Cynthia Brown, Cassandra Butts, Linda Chard, Charles Clotfelter, Derek Douglas, Debbi Harris, Sara GoldrickRab, Helen Ladd, Susanna Loeb, Richard Kahlenberg, Sean Reardon, Steve Rivkin, Neera Tanden, and participants in workshops at the University of Wisconsin at Madison and the AERA workshop on controlled choice held in Washington, DC during September 15-17, 2006. Introduction The United States as made remarkable progress in improving the educational equity over the past half-century. In 1975, 22 percent of Black students dropped out of school, compared with 12 percent of Whites, yielding a gap of 10 points. This gap in the drop out rate declined by more than half by 2005. Over the same period, White-Black disparities in scores on standardized tests—the “achievement gap”— shrank from 36 points to 22 points, a decline of more than one-third. The numbers also suggest that considerable gaps remain and that the upward trend in outcome equity stopped or reversed more than a decade ago. The above reduction in the achievement gap, for example, occurred almost entirely in the years before 1990 (Harris and Herrington, 2006). There are numerous possible explanations for this recent stagnation. Some researchers focus on the cultures of racial minority groups that influence educational outcomes, such as the effect of hip-hop music on Black culture. Others focus not on culture per se, but on the fact that minorities are more likely to live in poverty and all students in poverty are more likely to be negatively impacted by poor health and high housing mobility. Still others focus attention on the schools themselves, including disparities in school spending, teacher quality, pre-kindergarten, and tracking. Minority and other disadvantaged students have also become increasingly concentrated in a small number of schools (Orfield, 2001). This has reversed the trend that started with Brown v. Board of Education that led to substantial racial desegregation, especially during the late 1960s and 1970s. If having more disadvantaged peers is harmful, then such a trend would reduce educational outcomes for the disadvantaged