Out of Sight Out of Mind--How Our Mobile Social Network Changes during Migration

In this work we use anonymous telecommunication data to investigate how migration influences the dynamics of mobile social networks. We analyze the evolution of social ties for an entire country over a period of 11 months, examining: tie strength, sociality level, distance of ties, and persistence of ties. We find changes in tie strengths pre and post migration, specifically at six months before and a month after migration and discover that on average it takes approximately seven to eight months to restructure ones social network at a new residential location following migration. Moreover, the strongest ties such as those between families and close friends appear to be independent of migration. These ties continue to persist at nearly constant rates, in stark contrast to the weaker ties whose persistence rates drop significantly. Finally, we quantify the interdependency between the persistence rate, social strength, and migration distance, as a result, we are able to estimate how likely a given tie would persist, given the pre-migration social strength and distance of migration.