空間的相互作用モデルの距離パラメターの地域的差異に関する考察

二重制約型モデルによるわが国28県における人口移動の分析事例

抄録

This paper examines regional difference in distance-decay parameters of a doubly-constrained gravity model, using a data set of the 1985 inter-municipal migration in Japan. The parameters are estimated for each of 28 prefectures. The model provides reasonably good representation of migratory flows for all the prefectures (Table 3).
The distance-decay parameters are distributed roughly in such a way that the prefectures of central Japan have more-negative estimates and those of peripheral Japan have less-negative estimates (Fig. 2) as if a nationwide map-pattern effect were operating. Simple correlation analyses reveal that the distance-decay parameter is significantly correlated with demographic variables relavant to migration volume and population size as well as socio-economic variabels, but rarely correlated with map-pattern variables (Table 4).
A stepwise multiple-regression analysis is employed to regress the distance-decay parameter on only those significant at the 0.10 level or less, among the 46 independent variables. As a result, 56% of the total variance is accounted for by 4 variables (Table 5): population density, growth rate of manufacturing workers, physical-structure index (Griffith and Jones, 1980) capturing a prefecture-specific map-pattern effect and out-migration volume from prefectures.
Taking into account their signs of standardized partial regression coefficients, it is concluded that the distance-decay parameter is more-negative in the prefectures which are high-densely inhabited, which suggests, in a sense, that urbanization has reached an advanced stage, where municipalities are well connected, where industrial locations have recently become stagnant and where large migratory outflows from prefectures do not take place, and vice versa.