The American Planning Association (APA) sponsors a membership survey every 10 years or so to assess what professional planners do and know. The APA uses the results to amend and validate questions for the national American Institute of Certified Planners (AICP) exam. In 2007 more than 95% (of nearly 5,000 respondents) reported learning planning theory, mostly at planning schools. When asked about the importance of this knowledge for current professional work most ranked it on par (2.2 out of 4.0) with economic forecasting, hazard mitigation, waterfront planning or institutional planning. Professionals report using their most valued knowledge within the context of specialised areas of competence: development review, zoning administration, urban design, neighbourhood development, coastal zone management, affordable housing and more. Theory for these practitioners represents a kind of specialised knowledge useful on some occasions, but not relevant for daily use on the job (Hoch, 2010).
Richard Klosterman recently completed his fourth survey of planning theory course syllabi from instructors at US planning schools (2010). Comparing the reading assignment citations over more than three decades he found a modest minority of faculty staff using the same textbook essay collections, but mostly instructors relied on unique readings. So the popularity of specialised knowledge among practitioners appears to hold true for planning theory instructors as well. Planning theory ideas for spatial planning do not show signs of convergence in the US.
In this Viewpoint I take hold of this specialised diversity by grouping contributions to planning knowledge in three discourse arenas linking each of three planning domains. I argue that the planning theory enterprise offers robust knowledge within these arenas, but that this success makes theoretical convergence for all domains unlikely. Instead of seeking integration of discourse about theory and method like the now-discredited rational model, planning analysts might focus instead on comparing and studying how people practice and teach the craft of plan-making. Convergence depends on the practical steps colleagues take to learn and judge how and what plan makers do. This shifts the goal of planning theory from establishing an intellectual foundation for planning to foster better ideas for plan-making. This shift does not displace or replace the fruitful explosion of planning knowledge binding field, movement and discipline together. We can and should build practical pathways for convergence even as we foster the scope and depth of specialised knowledge in diverse discourse arenas.
Field, movement and discipline
I want to argue that we distinguish planning theory ideas into three arenas formed between each of three spatial planning domains: 'field', 'movement' and 'discipline'. The planning field includes purposeful efforts to anticipate, influence and cope with urbanisation and its effects. Professional planners contribute to the field, but the plans of firms, governments, non profit agencies, civic associations, community groups and countless individuals account for most of the practical advice used to make and maintain spatial settlements. The planning movement refers to collective efforts to develop and promote the practice of spatial planning as a legitimate and useful organised practice and profession. Various social, political and civic associations and their members contribute to the movement. Professional associations like the Royal Town Planning Institute and the American Planning Association represent prominent but not exclusive planning movement institutions. The planning discipline describes efforts to study and teach spatial planning on the job, in the profession and at the university. Disciplinary knowledge consists of ideas and tools that people use to do spatial planning (see Figure 1).
Movement and field
Most planning theory ideas published in edited books such as the Hillier and Healey (2008) opus and journals like Planning Theory explore the relationship between the planning field and movement. …