Working Paper: CEPR ID: DP17809
Authors: Matthew O. Jackson; Stephen M. Nei; Erik Snowberg; Leeat Yariv
Abstract: We examine friendships and study partnerships among university students over several years. At the aggregate level, connections increase over time, but homophily on gender and ethnicity is relatively constant across time, university residences, and different network layers. At the individual level, homophilous tendencies are persistent across time and network layers. Furthermore, we see assortativity in homophilous tendencies. There is weaker, albeit significant, homophily over malleable characteristics---risk preferences, altruism, study habits, and so on. We find little evidence of assimilation over those characteristics. We also document the nuanced impact of network connections on changes in Grade Point Average.
Keywords: homophily; social networks; dynamic networks; undergraduate education; peer effects
JEL Codes: D85; I21; J15; J16; Z13
Edges that are evidenced by causal inference methods are in orange, and the rest are in light blue.
| Cause | Effect |
|---|---|
| homophily on gender and ethnicity (J15) | persistence of traits (D15) |
| individual traits (Z13) | network formations (D85) |
| homophily over malleable characteristics (C92) | changes in retained connections (J63) |
| ethnic homophily in study partnerships (C92) | GPA gains (I24) |
| female study partnerships with stronger students (C92) | improved GPA outcomes (I24) |
| similar patterns of ethnic homophily do not hold for male-only partnerships (J79) | GPA outcomes (I24) |