A modelling approach to economic geography that stresses the importance of the larger picture; for example, concentrations of local successful economic activity drive up land prices, which then discourages new entrepreneurs from locating there. Nobel prize winner Krugman (1998) Oxf. Rev. Econ. Policy 14, 2, 7–17 calls this the combination of centrifugal and centripetal forces. Fujita and Krugman (2004) Papers Reg. Sci. 83, 139 define this as ‘a body of research initially stemming from international trade theory which fundamentally attempts to explain the formation of a large variety of economic agglomeration (or concentration) in geographical space’.