Sengupta, U., Solomou, S., Alsharif, A., 2022.

Where is the Complexity? Exploring the Theoretical Frameworks in Simulative Urban Modelling

Complexity theories have been incorporated into urban planning research to describe dynamic and temporal urban processes demonstrating adaptive, anticipatory and emergent phenomena for some time. Related computational urban models have moved on from
the initial experiments testing hypotheses based on existing theories of cities. By moving away from aggregation-based models, and due to the growing popularity of data-driven simulative approaches, 'Simulative Urban Models' (SUMs) have increasingly embraced bottom-up approaches and decentralised urban dynamics. Despite the shift away from tests on generalised theories of cities, the configuration of SUMs still implicitly or explicitly operationalises theories at various stages/points. The assumptions incorporated from these theories can bias or limit model-based approaches in terms of their ability to engage with complexity in urban systems. This paper presents a new analytical framework to understand the range and point of incorporation of theories within SUMs. Previous attempts have discussed methods - under different disciplinary and multi-disciplinary contexts - ranging from quantitative urban modelling and system dynamics to mathematical spatial models. The focus of this new analytical framework is specifically on the theories in SUM methodologies within urban spatial planning, excluding transport modelling. Through the development of this framework, we trace the use of theories within SUM methodological development over time to understand their role. While there are several current operational 'computer-based geographical simulative urban modelling frameworks' being used
to support urban spatial research - reflecting the range of theories utilised - specific engagement with complexity theories remains unclear. Our attempt to explore genuine
engagement with complexity is based on a comprehensive understanding of the historic development and current theories utilised within existing SUMs.