System dynamics is a method for studying the world around us. Unlike other scientists, who study the world by breaking it up into smaller and smaller pieces, system dynamicists look at things as a whole. The central concept to system dynamics is understanding how all the objects in a system interact with one another. A system can be anything from a steam engine, to a bank account, to a basketball team. The objects and people in a system interact through "feedback" loops, where a change in one variable affects other variables over time, which in turn affects the original variable, and so on.
An example of this is money in a bank account. Money in the bank earns interest, which increases the size of the account. Now that the account is larger, it earns even more interest, which adds more money to the account. This goes on and on. Another example of a simple feedback loop which we have all experienced is adjusting the water tap to reach a desired temperature. You turn the faucet, feel the temperature, and compare it to the desired temperature. You continue to adjust the water, with smaller and smaller adjustments, until you reach the desired temperature.
What system dynamics attempts to do is understand the basic structure of a system, and thus understand the behavior it can produce. Many of these systems and problems which are analyzed can be built as models on a computer. System dynamics takes advantage of the fact that a computer model can be of much greater complexity and carry out more simultaneous calculations than can the mental model of the human mind.
Two examples of important questions addressed by system dynamics models are:
We have selected several introductory documents that might help you to find out more about the field of system dynamics. They provide an overview of the development, use, and educational applicability of system dynamics. These documents are in a format which is readable with the Adobe Acrobat Reader. If you need help with it, visit the Adobe Site or read our help page.
Road Maps: A Guide To Learning System Dynamics teaches the basic principles of system dynamics and introduces you to modeling and simulation.
The System Dynamics and Systems Thinking Resource Guide, a listing of organizations which provide system dynamics consulting, is also available for downloading.
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