JOURNAL zyxwvut OF REGIONAL SCIENCE, VOL. 21, NO. 1, zyx 1981 zy TOWARDS AN INTERREGIONAL DEMOECONOMIC MODEL* zyxwv Peter Gordon and Jacques Ledentt Forecasts of economic activity over a set of regions can be made with a variety of interregional economic models such as those of Isard [3] and Moses [6]. These models are devoid of demographic information. Alternatively, the evolution of a population in a spatial economy can be traced in some detail with the aid of interregional demographic models such as those of Rogers [7, 81. The latter are devoid of economic information. The case for integrating the two types of models rests on the inescapable fact that economic and demographic variables interact. On the one hand, regional changes in economic conditions induce migratory moves between regions; on the other hand, the location of households affects regional levels of economic activity as a consequence of households’ role as consumers and suppliers of labor. Thus, this paper proposes a simple interregional economic model having a demographic dimension (hereafter referred to as a demoeconomic model). Germane to the recent “eco-demographic” models developed by Schinnar zy [ 10,111 and Beyers [l], this model is first intended as a possible framework for the consistent forecasting-over time-of demoeconomic variables in a system of regions. It is also suggested in the hope that the gulf between interregional economic and demographic theories will eventually disappear. The large number of studies which regress migratory flows on vectors of economic variables suggest that the interaction between economic and demographic variables is widely acknowledged. Yet, the reduced form regressions are seldom developed from an explicit model. The human capital model is often alluded to, but it cannot really bear the weight of the large numbers of independent variables that are, in fact, used by empirical researchers. We will show that, in building an interregional demoeconomic model, insights emerge which are not available from either of the models cited above. Basically, our demoeconomic model couples an interregional input-output model with an interregional components-of-change model, exploiting the fact that both these models are linear. Assuming that all the necessary economic variables are given exogenously, the model allows us to solve for a set of age-specific net *The work described in this paper was carried out while the first author was associated with IIASA. thsociate Professor of Urban and Regional Planning and Economics, University of Southern California and Research Scholar, International Institute for Applied zyxw Systems Analysis (IIASA), Laxenburg, Austria, respectively. Date received July, 1978; revised, July, 1979. 79