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Abstract

The insightful comments by Salem, Saldiva et al., Galea, Dora, Carvalho and Capon & Siri highlight several important points that are worth our reflection as we consider the utility of systems thinking and the tools of simulation modeling in urban health.Several commentators emphasize the value of systems thinking as a conceptual approach that extends well beyond the use of specific systems simulation tools. Salem challenges us to use systems thinking to better understand the processes (often rooted in social, economic, historic, and political conditions) that shape health and health inequalities in cities. He also highlights how systems thinking forces us to be more deliberate and specific in our definition of "urban" (and what it means to live in urban areas) and also to grapple with the inherent complexity in understanding health-related processes. Galea also notes that the main value in systems approaches is likely to lie in how we conceptualize health determinants and articulate how they operate together to affect health in cities, with special attention to context dependency. Carvalho emphasizes the development of dynamic conceptual models that integrate very different types of factors and processes as the key benefit and value of a systems approach. Capon & Siri challenge us to think broadly and develop dynamic conceptual models not only of health in cities but also models that articulate the interrelations between human health and ecosystems more broadly.An important element of the use of systems approaches is the ability to incorporate and integrate various types of information (as noted by Carvalho) and also community and stakeholder input, enhancing co-production of knowledge (as alluded to by Capon & Siri and Dora). But these approaches also raise many challenges and necessarily highlight the many limitations of the information and data available, as noted by Dora. Ideally, this will stimulate the design of new studies and the collection of new data to fill many gaps in understanding that are likely to emerge as we develop conceptual systems models and begin to attempt their formal simulation.