Internal Migration during Japan's Period of Rapid Economic Growth

Abstract

The purpose of this paper is to evaluate the spatial and temporal influences of economic level at the prefectures of origin and destination on internal migration movements by using the unconstrained gravity model (equation 3). The data used covers gross inter-prefectural migration flows during the period of rapid economic growth, 1955-72. The data of personal income per capita are used as proxies for regional economic levels.
Unfortunately, statistical data for migration are affected by the size of statistical areas. Here, statistical data are standardized by equation 4. The standardized data (similar to velocity of migration), however, are not equivalent in terms of their representation because the size of origin and destination prefectures for each sample is varies. Here, the number of samples is also corrected according to the size of origin and destination prefectures by equations 6 and 7.
Firstly, the entire inter-prefectural migration flows are analyzed and the conclusion made is that (1) both incomes at destinations and origins have a positive effect on migration; (2) incomes at destinations are considered to be more important factors than those at origins, but those efficiencies are proved to be in decline year by year; and (3) for incomes at origins, their absolute effects have no remarkable changes, but as the effects of incomes at destinations decline, their comparative effects increase.
Next, the entire inter-prefectural migration flows are divided into: (1) two groups by income difference between destinations and origins; and (2) four groups by metropolitan and non-metropolitan types. Each group of migration is analyzed by the gravity model. Those results are shown in figures 4 and 7, which are excluded in this summary.
Finally, the out-migration flows for each of the 46 prefectures are analyzed by the origin-specified model (equation 8). It is found that, in each given year, for those out-migrants from less-advanced regions, destination income elasticities are very high. As for those from middle-advanced regions, those elasticities are lower though still in the plus, while for those from advanced regions, the elasticities are very low or turn to minus. Here, the temporal changes of these elasticities for each prefecture show that the elasticities increase in those less-advanced regions located mainly in the peripheral areas of Japan, while decrease in those advanced regions located in Japan's core area. The incomes which cause the elasticities to become zero are defined as critical incomes and their changes are shown in figure 10. Similarly, in-migration flows for each of the 46 prefectures are also analyzed by the destination-specified model (equation 9).