This model is derived from the paper "Nobody Ever Gets Credit for Fixing Problems that Never Happened: Creating and Sustaining Process Improvement" by Nelson P. Repenning and John D Sterman. See Insight 752 for a causal loop version of this model.

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Consider the following "Sustaining the Forest" model intended to provide another example of how unexpected the behavior of a web of extended interactions can be.

The interaction of a population of Moose and Wolves.

All you wanted to do was put a bird feeder in your yard to attract birds and make for a more pleasant morning. And...

To develop insights regarding a situation of interest there are a number of things should be considered to ensure a view of the relevant influences.

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There are about fifteen known archetypes with an interesting set of relationships among them.

There is a new version of this model at

Frequently Recurring Structures

There are limits to what one can infer from a qualitative model.

This model depicts the interactions of Aesop's Fable "The Boy Who Cried Wolf."

How a Savings Account works.

There's actually more to filling a swimming pool with water than you might realize.

All you wanted to do was put a bird feeder in your yard to attract birds and make for a more pleasant morning. And...

The structure responsible for rabbit population growth.

Yesterday's actions are responsible for the world we experience today. And today's actions are responsible for the world that we will experience tomorrow. The "Creating the Future" model is intended to provide a better sense of the common process associated with the unexpected unfolding of the future..

From Jay Forrester 1971 book World Dynamics, the earlier, simpler version of the World 3 Limits to Growth Model. Adapted by Geoff McDonnell from Mark Heffernan's ithink version at Systemswiki.org.

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Are there environmental/physical limits to humanity? Based on the Are There Limits? blog post by Tom Fiddaman.

When one undertakes to create a model there are a number of guidelines that are considered essential for consideration if there is to be a success with the model.

The Home Heating System can be used to demonstrate how we get caught in dilemmas and become victims of ourselves.

This Romeo and Juliet Model was adapted by Geoff McDonnell from Michael J Radzicki (1993) Dyadic processes, tempestuous relationships, and system dynamics, System Dynamic Rev. 9 (1) :79-94

This model is derived from the paper "Nobody Ever Gets Credit for Fixing Problems that Never Happened: Creating and Sustaining Process Improvement" by Nelson P. Repenning and John D Sterman. See Insight 9781 for a simulation of this model.

This is a story based on the original Aesop's fable

The purpose of this model is to have the user change the value of stocks, flows and converters to experience a variety of different graphical results. Understanding this generic model is important pre-requisite to learning about intravenous drugs in the body, radioactivity, self-esteem, water flowing from a drain and many other basic natural systems.

New Learning tend to reduce Outdated Thinking, Communicating & Learning though our Outdated Thinking, Communicating & Learning inhibits new learning. The question is then how do we break this cycle. Adopted from "An Introduction to Systems Thinking with STELLA" by Barry Richmond.

When endeavoring to develop an understanding of the nature of something it is generally useful to create a model of some type to aid in surfacing that understanding.

This is a more Traditional Career Model of how education works, with an increased lifetime earnings from going to college. The following are links to the other two models in the series.

• Loan Cost Model
• Savings Model