Exploring socioeconomic friendship segregation in schools [electronic resource]
Keywords: Education.

The reproduction of inequality across generations, despite the best efforts of schools, and the corresponding achievement gaps by socioeconomic status (SES), are important topics in the field of education. This dissertation identifies a previously unstudied mechanism for the reproduction of inequality along socioeconomic lines: SES friendship segregation in schools. If high-SES students do not form friendships with less well-off students, then the social capital imparted by friends that influences academic outcomes will accrue only to high-SES students, giving them an additional advantage. While numerous qualitative studies point to the importance of the SES of friends, no empirical research has provided a thorough analysis of the level of SES friendship segregation in the United States. I uncover the causes and consequences of SES friendship segregation in three papers. The first paper describes the level of SES friendship segregation in a nationally representative sample of schools. I find that friendships are less segregated than expected, and that race is a more salient factor for friendship formation than SES. The socioeconomic composition of a school is strongly correlated with the number of cross-SES friends students form. If there is no SES diversity in a school, it is not possible for students to form diverse friendships. Other factors also limit opportunities for cross-SES interactions, such as residential segregation, segregation into different courses, and differential participation in extra-curricular activities. After the tendencies for students to reciprocate friendships and form friends of friends are modeled, and additional student characteristics are controlled for, there is no statistically significant relationship between student SES and friendship formation in many schools. Opportunities for interaction explain much of the patterns of friendship segregation, rather than preferences. In addition, I find that there are some more segregated communities within each school, close friendships are slightly more segregated, and there are no differences by gender or across grade levels. In my second paper, I look at whether the socioeconomic composition of a student's friendships in high school is related to his or her educational attainment. I find that the SES of a student's friends significantly predicts a student's educational attainment. In particular, students who have friends whose parents went to college are more likely to also make the transition to college. There are no differences by gender and both low and high-SES students are helped by high-SES friends. This paper shows that the socioeconomic composition of friendships matters and that students transmit social and cultural capital through friendships. In my third paper, I look at whether school characteristics explain variation in friendship segregation between schools. I find that high-SES friendship segregation is mostly predicted by the share of high-SES students in the school and that schools with course tracking also have more isolated high-SES students after controlling for the composition of the school. The preference for same-SES friends is also related to the diversity of the school: students in more diverse schools are characterized by greater preferences for cross-SES friends, though this decreases for the most diverse schools. Because higher SES friends are associated with higher educational attainment, I also investigate whether or not schools with greater friendship segregation have larger achievement gaps. I find that schools with greater friendship segregation do have larger achievement gaps, even after controlling for other school characteristics.