Working Paper: CEPR ID: DP13822
Authors: Johannes Stroebel; Michael Bailey; Theresa Kuchler; Patrick Farrell
Abstract: We use anonymized and aggregated data from Facebook to explore the spatial structure of social networks in the New York metro area. We highlight the importance of transportation infrastructure in shaping urban social networks by showing that travel time and travel costs are substantially stronger predictors of social connectedness between zip codes than geographic distance is. We also document significant heterogeneity in the geographic breadth of social networks across New York zip codes, and show that much of this heterogeneity is explained by the ease of access to public transit, even after controlling for socioeconomic characteristics of the zip codes' residents. When we group zip codes with strong social ties into hypothetical communities using an agglomerative clustering algorithm, we find that geographically non-contiguous locations are grouped into socially connected communities, again highlighting that geographic distance is an imperfect proxy for urban social connectedness. We also explore the social connections between New York zip codes and foreign countries, and highlight how these are related to past migration movements.
Keywords: social connectedness; agglomeration; externalities; transportation infrastructure
JEL Codes: R1; R2; R3
Edges that are evidenced by causal inference methods are in orange, and the rest are in light blue.
| Cause | Effect |
|---|---|
| travel time (R41) | social connectedness (Z13) |
| geographic distance (R12) | social connectedness (Z13) |
| socioeconomic similarities (P36) | social connectedness (Z13) |
| differences in racial composition (J15) | social connectedness (Z13) |
| differences in educational attainment (I24) | social connectedness (Z13) |
| public transit investments (R42) | social connections (Z13) |