Abstract for: System Dynamics: Re-basing the Paradigm

“When faced with a new problem, I start by identifying the stocks and how they are changing. I do not try to develop causal loop diagrams, though I know this is popular.” Forrester J, 2013. There has been much recent debate about how the uptake of System Dynamics might be accelerated - suggesting a fundamental reconsideration of how it is practiced might be in order. System dynamics projects commonly start with defining how issues of concern are changing over time, then moves to the building of qualitative causal-loop diagrams with those involved, after which model structures with stocks and flows are drawn up and data sought with which to populate and formulate those structures, so as to create a working mathematical model. The process is difficult, time-consuming and unreliable (in the sense that there is a high risk of models with serious flaws and omissions, and that different models of the same situation will differ substantially from each other) – a weak foundation for a professional method. Reconsidering the method's basic science suggests that the second step is unnecessary, and that model-building can go straight from how the issue of concern is behaving to a quantified mapping of how stocks and flows are changing. From there, interdependencies can be traced – again with quantified support – and significant feedback mechanisms identified. Resulting models are more likely to be demonstrably valid, and easier and faster to build, making system dynamics both more accessible and a more reliable professional tool.