Polycentric urban regions and the quest for synergy: Is a network of cities more than the sum of the parts?

Polycentric urban regions, or urban networks, are often associated with the notion of synergy, the assumption being that the individual cities in these collections of distinct but proximally located cities relate to each other in a synergetic way, making the whole network of cities more than the sum of its parts. Drawing on economic network theories, an analysis of the presence of synergy is carried out for the Randstad region in the Netherlands, which is often considered a classic example of a polycentric urban region. The analysis focuses on the synergy mechanisms of co-operation and in particular complementarity. The results are mixed. In terms of co-operation, the Randstad has become more synergetic. However, the less complementary economic roles of the cities caused a reverse effect.