Unfolding community homophily in U.S. metropolitans via human mobility

As described in the proverb “birds of a feather flock together”, the term homophily narrates the principle that stronger spatial interactions tend to be formed among locations with similar characteristics. Taking advantage of mobility networks derived from around 45 million mobile devices in the U.S. and targeting the top twenty most-populated U.S. Metropolitan Statistical Areas (MSAs), we extract human mobility structures by detecting communities formed by strong spatial links and unravel the homophily effect at the community level using information entropy that measures the chaoticness of societal settings within communities. The results suggest that the power-law still, to a large extent, governs the travel patterns in MSAs. However, communities featured by strong human interactions can sometimes transcend geographic proximity in modern metropolitans. The entropy varies across communities, and a community can exhibit variation of homophily levels when different sociodemographic settings are investigated. Our study proves the ubiquity of the homophily phenomenon in modern metropolitans and documents its variation from different social perspectives from a mobility-oriented setting. The conceptual and analytical knowledge, as well as the results of this study, are expected to facilitate better policymaking to promote social integration in metropolitan areas. • We reveal the similarity and dissimilarity of mobility profiles in the top twenty most populated U.S. metropolitan areas. • We introduce “community entropy” to reflect the chaoticness among community members formed by strong spatial interactions. • The homophily levels vary across/within communities when different sociodemographic settings are investigated. • The results call for place-based planning and developing community initiatives for a more integrated and harmonious society.