A Spatial Model of Growth: Taking Technology Seriously

This paper attempts to develop a spatial model of economic growth in which technology and externalities are assumed to be accountable for production in geographical space. Linking externalities to the extent of intensity of production across locations in continuous space, we introduce spatial range into the production function for technological, human, and physical capitals. Our model argues that the long-run growth rate of an economy is determined not just by the growth rates of the three factors of production but by their rates of change in spatial range over the territory of the economy. In other words, spatial intensity and accumulation matter for growth. Our model is consistent with studies on knowledge spillovers, geographical agglomeration, urban and regional growth, and trade. The primary policy implication of our model is the significance of establishing efficient mechanisms or channels that promote innovation, diffusion, trade, and factor mobility over the territory of an economy. It is not as if we always have it everywhere, but there is a process in which knowledge is being created all the time in different places, and is then being diffused. This evolving distribution should be reflected in a model of production, if it is to describe an entire economy in which different people know different things. As a consequence, the idea of an aggregate production function becomes very dubious, unless a new variable is introduced, representing the distribution and diffusion of new knowledge.