Initial determinants of Mexican mass migration

by David Escamilla-Guerrero (London School of Economics)

This paper was presented at the EHS Annual Conference 2019 in Belfast.

We are living in a time of globalisation backlash characterised by a reduction of economic and political cooperation across borders. The renaissance of economic protectionism has manifested in increasing barriers against immigration in both the United States and Europe. Furthermore, the public perception of why people migrate seems to be increasingly influenced by nationalist prejudices rather than empirical evidence.

Using novel historical micro data, my research addresses the initial determinants of the Mexico-US migration, the most intense and persistent of the twentieth century. The main lessons to take are two-fold:

• First, the push and pull factors influencing migration vary across regions of sending countries.
• Second, we have focused our attention on wage differentials between countries as main determinant, overlooking the role of structural differences within sending countries.

The core data of the research come from manifests that recorded individual border crossings. These documents are known as Mexican Border Crossing Records and were used by American authorities to collect information about immigrants. The sample used in this research consists of 10,895 immigrants that crossed the border through eight ports of entrance from July 1906 to December 1908.

The results reveal that differences in the Mexico-US relative wage did not explain the migration flow. But differences in living standards and population size across Mexican municipalities mattered. On average, locations with low living standards and large populations represented a source of frictions in the Mexican labour market, pushing labourers to migrate.

In addition, the estimates show that the flow was consistently driven by the social capital formation in the destination – that is, immigrant networks. Just as found for recent periods, migrating to a county with a large Mexican community increased the net benefits of migration.

Therefore, for more than one hundred years, immigrant networks have represented a self-perpetuating social asset that provides information and assistance, which reduces the costs and risks of migrating.

The regional results reveal that there were two migration models at the time:

• In the border region, distance costs and labour market potentials in the United States influenced the decision to migrate.
• In contrast, migration from the Mexican central plateau was completely determined by immigrant networks and labour market pressures in Mexico.

Since 2010, Mexican migration to the United States has come to a standstill, although the salary gap remains at levels like those of the early twentieth century. Hence, the persistence of immigrant networks as the main driver of the Mexico-US migration raises the question of whether the convergence of real wages between home and host countries would be an effective mechanism to reduce or control migration.

An integral migration policy must consider the different incentives behind the decision to migrate as well as their evolution through time and across space. Only then, will we maximise the benefits of labour migration and minimise the problems derived from it.