The decision to migrate

The emotion and hope of a new life, perhaps in a place full of opportunities and promises, guide one of the most important decisions an individual can make: migrating. But what really influences this crucial choice? Experts agree that social networks play a fundamental role. An innovative study, recently published in the prestigious American economics journal, Review of Economic Studies, uses detailed digital data to explain how social networks in destination countries influence the decision to migrate.

Previous studies highlight two distinct mechanisms: on the one hand, social networks provide migrants with access to information, for example about jobs and living conditions in the destination; on the other hand, they represent a safety net for migrants by providing material or social support. However, there is considerable ambiguity about the nature and relative importance of these two mechanisms. These ambiguities arise in part because it is difficult to link the structure of social networks to migration choices using traditional data. Most previous works use indirect techniques to estimate a migrant's social network. While, on the one hand, these techniques provide a reasonable approximation of the size of a migrant's social network, they do not explain, on the other hand, whether and how other aspects of the social network structure influence the migration decision.

Through a rich new source of data based on “digital traces”, the authors manage to give a more specific empirical explanation to the role of social networks on the decision to migrate. This data is based on mobile phone activity in Rwanda for 5 years: every time users make or receive calls, their approximate location and the identity of the person they talk to can be used. From this data, the authors build the migration dynamics of each subscriber, as well as a detailed picture of their social network before and after migration.

The results are surprising. First of all, Migrants tend to prefer places where they have many contacts, and therefore, for this very reason, they are less inclined to leave places where they have many contacts. As the number of contacts in your city increases, the probability of leaving your residence decreases.

The second result shows that migrants are mainly attracted to destinations where their contacts are interconnected. By focusing the analysis on a sample that consistently has two contacts in the destination, the authors estimate that migration rates are higher when an individual's two contacts become more connected than when they become more disconnected. This suggests that the cohesion of the social network in the destination country, providing “cooperation capital”, plays a critical role in the choice to migrate.

The third result highlights that "information capital", typical of more extensive networks and therefore capable of transmitting information efficiently, does not play a fundamental role: the average migrant is not attracted to destinations where his contacts have many other contacts ( friends of friends). This effect appears to be due to potential rivalries in information sharing within networks, pushing migrants to value connections with people for whom there is less competition for attention.

Rereading the authors' results from another perspective, it would seem that what most pushes a person to migrate is the "quality" of the destination network, on which they can count for social support and cooperation, rather than the "quantity" of contacts , i.e. the number of potentially known or knowable people who could be used to obtain relevant information on the context, such as "tips" on the job market in the destination country.


Pierluigi Conzo
NP May 2024