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Archive for December, 2009

Top Blog Posts of 2009

December 18th, 2009 2 comments

isee_blog_icon_128In 2009, the isee systems blog, “Making Connections” was created as a forum for sharing ideas and experiences with the Systems Thinking community. Blog topics cover subjects ranging from a systems perspective of current news events to modeling tips for advanced STELLA and iThink users.

As the first anniversary of the isee Blog approaches, we thought it would be interesting for folks to see the list of our most popular blog posts.


Top Ten Posts of 2009

  1. Modeling H1N1 Flu Outbreak
  2. Modeling Customers Switching Between Brands
  3. Modeling a Watershed with Arrays
  4. Matrix Arithmetic
  5. Spatial Modeling with isee Spatial Map
  6. “Thinking in Systems” book inspires online course
  7. Physics Textbook 2.0
  8. Insight-based Model Investigates the Housing Crisis
  9. Building a Health Care Model Hierarchically
  10. C02 in the Atmosphere Behaves Like a Bathtub
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Limits to Growth

December 3rd, 2009 5 comments

This is the first of a three-part series on the Limits to Growth Archetype.  The second part can be accessed here and the third part here.

The Limits to Growth Systems Archetype, also known as Limits to Success, combines growth with an exogenous or endogenous limit.  This Systems Archetype was formally identified in Appendix 2 of The Fifth Discipline by Peter Senge (1990), but made its first prominent appearance in World Dynamics by Jay Forrester (1971) and then The Limits to Growth by Meadows, Meadows, Randers, and Behrens (1972).  The Causal Loop Diagram (CLD) is shown below.

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Real growth processes have inherent limits to growth.  Identifying these limits can help avoid problems in the future, whether the problem is overpopulation, increasing demand for a product that cannot be met, or growing a business in a mature market.  When growth is desired, but limited, it is always better to find ways to increase the limit before pushing for more growth.  Excessive growth in the face of a limit often leads to collapse.  Driving the system to the point of collapse can erode the ability to continue after the collapse, for example, by reducing the production capability of a piece of farmland or destroying the reputation of a company.

Classic examples of limits to growth include:

  • The collapse of the deer population on the Kaibab plateau and on St. Matthew Island due to overpopulation and the attendant overgrazing of their habitat
  • The overshoot and collapse of the human population on Easter Island
  • Overgrazing in the Sahel region of Africa by cattle herders
  • Overfishing of the oceans by fishermen
  • The collapse of People Express due to sharp customer growth combined with slow personnel growth
  • The sharp exodus of America Online subscribers after an intense marketing campaign increased the number of subscribers far beyond their capacity
  • The contraction of the world economy in 2008 due to limiting oil supplies
  • The productivity of staff deteriorating as a company grows, due to increased interactions and reporting overhead
  • Business growth limited by the size of the potential market
  • Yeast cells in the fermentation process, who suffer from both the loss of exogenously supplied sugar and the increase of endogenously produced pollution

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