The origins and use of theory in urban geography: Household mobility and filtering theory

The paper looks in detail at one particular interpenetration of academic theory and state policy making — filtering theory in urban geography. While household mobility and turnover are important processes in the housing system, they are extended in filtering theory to form a universal explanatory model embracing the entire housing system. In this model idealised concepts of the operation of the housing market—valid only under conditions that do not occur in practice — are used to legitimate a laissez-faire natural-market view of how the housing system should operate. Translated into government policy, used to justify the dominant private interests in housing, and supported by academic explanation, the theory then comes to legitimate the persistence of gross inequalities in housing provision and to maintain the allocation of resources away from those most in need. This paper reviews this use of filtering theory both in Britain and the United States, and makes a variety of empirical and theoretical criticism of its validity.