Ethnic segregation is a striking feature of many contemporary societies. Yet, due in part to constraints of existing data, empirical efforts to study the determinants of segregation have been limited. In this paper, we exploit a novel source of data to model the impact of migration and urbanization on segregation in a small society.
The focus of our empirical analysis is Estonia, a country whose complex geo-political history has led to a status quo where two dominant ethnic groups – ethnic Estonians and ethnic Russians – coexist in a stratified society that Heidmets (1998) has described as one of “silent separation,” where the two ethnic groups occupy the same physical spaces but rarely interact. We analyze the complete mobile phone records of hundreds of thousands of Estonians, which allows us to observe the ethnicity of each individual (Russian or Estonian), the complete history of locations visited by each individual, and every phone-based interaction that takes place over the network. Together, these features offer a unique perspective on the structure of ethnic segregation in Estonia, as well as the role that migration plays in processes of segregation.
Initial results indicate that the ethnic composition of an individual’s physical neighborhood is highly correlated with the ethnic composition of the individual’s social network: people who are physically surrounded by co-ethnics are more likely to be in phone contact with co-ethnics. We further find that patterns of segregation are significantly different for migrants than for the at-large population: migrants are more likely to interact with coethnics than non-migrants, but are less sensitive to the ethnic composition of their immediate neighborhood than non-migrants. Interpreted these results with a nested search-based model of friendship formation, we test between different determinants of ethnic segregation in Estonia.