The Theory of City Size and Spacing

The theory of city size has attracted a great deal of attention in recent years. The literature has concentrated on two distinct but nevertheless related issues. The first of these involves the definition of the most desirable ‘optimal’ city size. Discussion of this question has been far-ranging, involving not just economists but also sociologists, town planners, social psychologists and ecologists to name but a few. In a purely practical sense it is particularly difficult to reach any firm conclusion in this area because of the lack of really relevant information and the immense difficulty of quantifying many of the considerations important to the debate. These are problems additional to the theoretical difficulties involved, but the lack of a solution in the short term suggests it is unlikely that any of the various theories of optimality which have been advanced will be empirically substantiated in the foreseeable future. These practical and theoretical problems often distract from the far more important question of whether an optimum size of city can ever be defined satisfactorily or, indeed, whether it is important to attempt such a definition. The general argument to justify work in this area is that local authorities need some idea of the optimal-size population they should encourage to settle in their cities but, as we shall see later, this can lead to various conflicts of interest.