Research over the past two decades has established the centrality of social networks to the process of international migration. As social beings, humans are inevitably enmeshed in webs of strong ties to close friends and relatives and weak ties to more distant relatives, casual acquaintances, and friends of friends. The set of weak and strong ties to people with current or prior migratory experience constitutes a person’s migrant network. Whenever an aspiring international migrant has a social tie to someone with prior migratory experience, that connection offers a potentially valuable source of social capital. By drawing on the tie, individuals can mobilize social capital embedded within it to gain access to valuable information, moral support, and material assistance that may reduce, often quite substantially, the costs and risks of international migration. As a result, people who have migrant friends and relatives display a much higher likelihood of migrating compared with those who do not.

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