Association for Public Policy Analysis & Management

A large literature documents the importance of migrant networks in key migration decisions. Networks affect the probability of migration and where migrants choose to locate, and stronger networks lead to improved labor market outcomes after arrival. Much of this previous work has uncovered these relationships despite important limitations in available data sources on migrant networks. Commonly used survey data either i) cover only a small fraction of sending- or receiving-country locations or ii) provide very coarse geographic information, potentially obscuring differences in networks at finer levels of geography.

In this paper, we show how to use administrative data from the Matrícula Consular de Alta Seguridad (MCAS) identification card program to measure migration networks with complete geographic coverage of both Mexico and the U.S. Further, these data provide very detailed information on Mexican sources (more than 2,000 municipios) and U.S. destinations (75 states/consular areas). Because these are tabulations from administrative data and not surveys designed to be nationally representative, we first confirm the quality of the MCAS data by comparing them with well-known household surveys in Mexico and the U.S. This analysis reveals strong agreement on both marginal (within a single country) and joint (source-destination pairs) location distributions measured commonly across datasets.

We then demonstrate the importance of using data with detailed geographical information by documenting substantial differences in migrant networks across geographic areas within the same source state. These differences are unobservable in datasets with more aggregate geographic information, and relying on coarser information likely obscures the true importance of migrant networks in influencing migrants' choices and outcomes.

We then use this information to examine how ties to a particular destination in the United States affect outcomes in sending locations as the U.S. labor market changes. In our initial work, we rely on the Legal Arizona Workers Act (LAWA), which mandated e-verify statewide in Arizona. This policy made it much more difficult to find employment for migrants without legal authorization to be in the country. We find decreases in emigration rates and increases in return migration rates in sending communities in Mexico that historically sent a larger share of migrants to Arizona. These changes are substantially different than changes in migration rates over the same time period in communities with weaker ties to Arizona. Importantly, we measure these changes in migration rates using data from the Mexican Census, and thus only the network measure is derived from the novel data source. We also conduct corresponding analysis using data at the Mexican state level. The results are of a similar sign and magnitude, but they have much less statistical precision, which further reinforces the value of the more precise measurement of place-based migration networks.

We plan to extend this analysis to include additional labor market and human capital investment outcomes in Mexico. Further, we intend to pursue additional analysis using variation in U.S. destination labor market shocks arising as a result of the Great Recession.