System Dynamics Applications / 1 / 1.5

1.5 ABOUT SYSTEM DYNAMICS MODELLING

In just over 40 years, system dynamics modelling has developed into a well-established body of knowledge. The system dynamics modelling discipline challenges conventional thinking about problem situations where changes over time are part of the problem. Such problems are known to confound our attempts to design and implement effective and enduring management interventions.

Wolstenholme (1990: 3) defines system dynamics as:

A rigorous method for qualitative description, exploration and analysis of complex systems in terms of their processes, information, organisational boundaries, and strategies; which facilitates quantitative simulation modelling and analysis for the design of system structure and control.

Dynamic problems we try to manage are frequently the product of a large numbers of variables, many of which are strongly related to one another. This is a characteristic of complex, dynamic problems. Dynamic complex problems are also characterised by having response to input that is neither instantaneous nor directly proportional to input (or disturbance). Further, that response may continue after the input is stopped or held constant. In dynamic real-world social, economic, or socio-technical problems it is rare that we can stop the input so that we can separate out the various effects created by it.

Gaining a comprehensive understanding of complex dynamic problems is a serious challenge. But, if we successfully rise to the challenge, the rewards can be colossal. Here, it is argued and demonstrated that to build real understanding we need to be able to build models taking into account a systems view of the problem of interest. That is, our systems view enables us to identify and systematically explain how the interconnections between variables and the structure of the problem combine to produce over time the behaviour we have observed.