The Institute for Economic Development at Boston University -------- ------------------------Research Review Spring 2001

The Effects of Proximity and Transportation on Developing Country Population Migrations”

Robert E.B. Lucas
IED
Discussion Paper 111, November 2000

While economists have traditionally been averse to immutable laws, Ravenstein’s law of migration, which in its general form states that the number of people migrating between two regions is inversely proportional to the distance between them, controlling for population size, has stood the test of time well. Both in industrialized and developing countries, and with respect to both internal and external migration, greater distances do indeed deter movement. Given this regularity it is quite remarkable that we understand very little about the underlying causes behind this deterring effect of distance. In development economics, migration has been of interest solely as a process of transferring labor from the agricultural sector to the industrial sector. Proximity or remoteness of a village from an urban center was generally neglected and development models glossed over rural–rural migration by assuming a uniform rural sector.

This paper by Lucas seeks to address two questions related to the issue of distance. First, why should distance play such a pervasive and persistent role in migration patterns? Second, what are the economic consequences of distance as a deterrent to migration? With respect to the first question, Lucas concludes that information about remote locations may be costlier to acquire, thus making longer moves riskier.

Moreover, the single-most important source of information for potential migrants is the network of previous migrants. Lucas also suggests two other important sources emanating respectively from labor and asset market characteristics of the migrant. In particular, if labor markets tend to be more homogeneous locally, unemployed migrants may migrate shorter distances to better transfer their job skills. If the potential migrant has asset holdings in his village, then shorter distances make for better monitoring and control of these assets. Turning to the question of why we should be concerned about the centrality of distance in explaining migration patterns, Lucas points to the impact upon the difficulty of out-migration from remote and poor regions leading to the generation of poverty traps. Lucas looks at a number of natural mechanisms that serve to perpetuate this problem. A combination of a brain drain effect and economies of scale in production serve to exacerbate the preexisting economic distance between regions. Other important contributing factors include the dwindling amount of remittances from out-migrants that serve to simultaneously lower household incomes in remote areas and indirectly remove an important insurance buffer for bad times.

The paper concludes with a number of suggestions for both additional research and data needs on the one hand, and also suggestions intended to better inform policy decisions that impinge upon the geographic distribution of poverty, and hence upon the potential for trickle-down development.

Page 7
Table of Contents
IED Home page
Updated: 7/11/01