From modest origins as specific types of state-interest group relations, policy network approaches have developed in a series of phases, with the appearance of network typologies, interorganizational analyses and diversified frameworks. To understand and judge network approaches, it is necessary to analyse their achievements relative to their ambitions. Such an analysis shows that each phase has seen expansion of the scope and ambitions, as approaches have sought to offer not just metaphors, but also description and different forms of explanation. Continuous expansion has allowed network approaches to be adaptable, but the result has been an increasing gap between their aims and achievements. Determining the appropriate scope and ambitions for network approaches depends on the choice of their fundamental purpose and role, together with their relationsip with substantive hypotheses and models.
