Planning historians, now and in the future, first and foremost have be convincing in their privileging of planning as an analytical framework for historical analysis. They have to provide compelling accounts that show why a focus on planners, planning ideas, and planning practice is more illuminating than one on social practices, political events, or economic conditions. In short, the have to give conclusive answers with regard to why they engage in planning, and not for example in social or economic history.

In my opinion the persuasiveness of planning history hinges on two factors: the existence of planning as a consistent intellectual framework and the palpability of this framework in the urban fabric. Both were particularly evident during the period of modern planning approximately from the mid nineteenth to the late twentieth century.