The role of analytical models and their circulation in urban studies and policy

Using and building analytical models of cities over a certain time, you start noticing two trends. First, some models are taken for granted, which means that the Schelling model of segregation is systematically called to use for basic segregation simulations, the rank-size curve – to analyze city size distribution, and so on. Second, and because of the familiarity that such models have acquired over time in the field of urban studies, the assumptions on which they rely can become obscured, distant and unquestioned when we apply them to particular case studies, leading to dubious results, questionable conclusions and contentious policy recommendations. For instance, simplifications made for the sake of computational speed, equation solvability or model readability can lead to a change of results when relaxed, and therefore not apply to empirical case study (think about the linear city of economic geography, the costless nature of residential moves in Schelling’s model, etc.). Additionally, some assumptions are very context-dependent despite the canonical nature of the model and therefore cannot/should not apply everywhere. This is the case for Alonso's monocentric city model, which assumes individual ubiquitous transport and the valuation of living space over other aspects of housing, an assumption very suited for the motorised urban society in which the model was developed, but by far not a universal one. Although the movement of decolonisation of knowledge seems to have gained momentum in urban theory and policy analysis, the domain of analytical urban models seems to lag behind.

We therefore set ourselves to review a canonical set of analytical urban models in a series of seminars and to compare their circulation across the fields of urban studies and urban policies, in order to disentangle the elements of the models which pertain to contextual contingencies from those which constitute essential features of the models. In this paper, we borrow the theoretical framework of the policy mobilities literature and focus on the circulation of analytical models. Our innovative take lies in the reflexive assessment of analytical urban models, by analytical modellers and practitioners involved in the field as creators and intermediaries of the models' circulation.

We think that this exercise is important because analytical urban models are needed to understand, plan and manage cities around the world. These models are becoming modular and complex, assembled from reusable building blocks. Canonical models are the most obvious candidates for such building blocks, being simple and robust. However, their assumptions need to be known, assessed, selected and evaluated so that essential features can be distinguished from contingent elements of their context of production.

Read the full open access article on Urban Studies OnlineFirst here.