System Diagrams are Models used to visually express the dynamic forces acting upon the components of a process and the Interactions between those forces.
System Diagrams are more than process Flow Charts. They include feedback loops and other Factors that influence how decisions are made, including attitudes, perceptions, and behaviors. If you are familiar with the terms "vicious circle", "downward spiral", "the law of unintended consequences", or "the cure is worse than the disease" you are familiar with some of the basic concepts of System Dynamics. System Diagrams provide a common language to help organizations think about these complex issues.
Efforts to improve the performance of complex systems inevitably touch on many areas directly and indirectly, so it is critically important to understand the potential for unintended consequences. It is also important to understand the true leverage points to improve a system, which probably won't be obvious.
MoreSteam toolbox - System Diagram - http://www.moresteam.com/toolbox/system-diagrams.cfm