Domestic change of people’s place of residence is not simply a movement of individuals between two points. Instead, it can be regarded as a social phenomenon in which people migrate on the basis of the economic factors of the two regions. A typical example is urbanization, in which there is population concentration in a single area. It is an important research theme of the social sciences to clarify the economic factors that lead to population migration and the economic impact that migration has on both the area of origin as well as the destination.
Therefore, in this paper, I have overviewed earlier theories about population migration by dividing them into two: a conventional population migration theory based on neoclassical economics and a new
population migration theory premised on increasing returns based on spatial economics. Then, I showed that it is possible to explain that the over-concentration of population in Japan’s Tokyo is a result of the economics of urbanization based on increasing returns. I also demonstrated the necessity of an approach from the new perspective of the economics of urbanization in regard to the issues of economic development in developing countries. Further, I clarified issues regarding endogenous selection bias and the handling of population migration data in performing an empirical analysis of population migration.
