The need to consider internal migration in development efforts can hardly be emphasized since some of the most acute social and economic problems of the world and of the country today are associated with population movements. The fact that the large concentration of population in Metropolitan Manila has been mainly the result of rapid rural-to-urban migration, for instance, is amply documented. It is pointed out in this regard that the continuing trend towards concentration has brought about increasing interregional and rural-urban disparities in terms of social and economic progress and welfare conditions in the country. The lag of certain regions due to the massive loss of manpower has also been another source of concern. In the receiving areas, migration is also pointed to as the root-cause of such urban phenomena as the breakdown of services, congestion and traffic snarls, slums and squatters, and other related urban problems.
The significance of population movements on development may indeed be obvious in that they provide an important network for the transmission and diffusion of ideas, indicate symptoms of economic and social change, and can be viewed as the adjustments of people to development problems in the broadest sense. Thus, it is not only because of basic academic interest but also because of this crucial link of migration to development processes and problems that the phenomenon has been the subject of quite a number of social science research in the Philippines.