This presentation provides an introduction to system dynamics. Peter S. Hovmand, PhD, MSW Founding Director, Social System Design Lab Brown School of Social Work Washington University in St. Louis

1. Introduction to System Dynamics
Peter S. Hovmand, PhD, MSW
Founding Director, Social System Design Lab
Brown School of Social Work
Washington University in St. Louis
November 2011 WUHM Meeting 1

2. System Dynamics
• Field invented by Jay W. Forrester at MIT in 1958
• System dynamics:
– “The use of informal maps and formal models with
computer simulation to uncover and understand
endogenous sources of system behavior” [emphasis
added] (Richardson, 2011, p. 241)
• Foundations of system dynamics:
– Endogenous perspective
• Stock or level (state) variables representing accumulations
– Flow or rate variables representing activity
» Using computers to simulate more realistic mathematical models
Richardson, G.P. (2011). Reflections on the foundations of system dynamics. System Dynamics
Review, 27(3), 219‐243.
November 2011 WUHM Meeting 2

3. Model Based System Insights
Informal Modeling Formal
Surface
system
insights
There is a system Informal
The components of a system maps
How the components are related through feedback
How people might think about a system
Where one could intervene
Depth
What is transformation
What is the generic structure
What are the implications of accumulations and nonlinear
relationships
What systems can generate the dynamic behavior
Where are the leverage points
insights
system
Deep
When do boundary conditions determine behavior
Why do things happen Simulation
models
November 2011 WUHM Meeting 3

4. Examples of different uses of models
• Raise awareness and promote learning about
complex systems
• Motivating discussions about the need to
involve multiple stakeholders and solve
coordination problems
• Policy analysis and design
• Motivate change
November 2011 WUHM Meeting 4

5. Todays’ design discussion
• Urban Health Model
– Overview of the model and interface
– Hands‐on experience with using the model and
prototype interface
• Design discussion
– How could you imagine using the model?
– Who would you use the model with?
– What would need to be developed to facilitate
that use?
November 2011 WUHM Meeting 5