What is System Dynamics?
"System dynamics deals with how things change through time, which includes most of what most people find important. It uses computer simulation to take the knowledge we already have about details in the world around us to show why our social and physical systems behave the way they do. System dynamics demonstrates how most of our own decision-making policies are the cause of the problems that we usually blame on others, and how to identify policies we can follow to improve our situation." - Jay Forrester, Professor of Management, Emeritus and Senior Lecturer, Sloan School, Massachusetts Institute of Technology; Founder, System Dynamics
System Dynamics is a computer based approach for modeling complex physical and social systems and experimenting with the models to design policies for improved performance. A model embodies a theory explaining internal dynamics of an abstract system built around a problem. The basic elements of a system dynamics model are stocks, flows and feedback loops. Stocks are things that accumulate, like the national debt or a business inventory. Flows are the movement of things into or out of a stock. The annual federal deficit is a flow into the stock of debt. Feedback loops convey information about the level in a stock, for example, that might that might change a rate of flow or alter some other element in a system. For example:
The implementation of system dynamics to address specific problems involves several carefully designed steps aimed at creating a clear understanding of the problem as well as the possibilities for system improvement. These steps include: 1) representation of a pattern of trends portraying the problem, for example, changes in flow rates or changes in the level of a stock, 2) identification of a causal map that qualitatively describes how the problem is created, 3) articulation of the decision relationships underlying the causal map into a computer model and 4) experimentation with the model to learn about the problem and the possible ways to mitigate it.
Student Profile
"I liked the wide range of options that system dynamics offered when I graduated. Today I work at Electric Boat Corporation, which designs, builds and supports the life cycles of submarines for the U.S. Navy. As an engineer, I've gained a broader perspective from system dynamics and a different way of thinking. I think about problems in terms of the cause-effect interrelationships in a system. And I've learned to recognize and fix problems, rather than simply address their symptoms." - Sarah Scharff '02
The modeling process can be as important at the model itself. This process assists people in identifying their assumptions and testing their beliefs and assertions about causal relationships in complex systems. Since the modeling process can present different insights and points of view in a more objective fashion, it provides a relatively neutral language and framework to help identify more subjective but also critical issues. A trained facilitator can greatly help to integrate expert knowledge into a model that represents the shared understanding of a group of people interested in the same problem.
Maintained by webmaster@wpi.eduLast modified: October 12, 2006 11:15:09