Growth of System Dynamics Policy Analysis

[shayneg@agsm.edu.au]

I recently received and read the most recent System Dynamics Newsletter
(formerly the Presidents Newsletter) for December 2001. The mail from
Albany takes a bit longer to reach us here in Australia! As usual, I found
the newsletter quite interesting and a very worthwhile read. As I was
reading Ali Mashayekhis A Vision for System Dynamics, I could not help
but wonder why our community has not developed AND debated a model that
would help inform policy discussions about the growth and sustainability of
our discipline. Ali himself makes the case for such a model based policy
analysis in his second paragraph when he says:

"The human mind is not capable of perceiving the dynamic consequences of a
number of simultaneous active feedback loops."

Most members of this list will recognize that the sentiments of the above
statement have been embedded in the foundations of system dynamics since
its inception. Why have we not developed a model to explore the
implications of various policies that may or may not impact the growth and
sustainability of our field? I was so convinced that someone must have
developed a model with such a focus that I searched the SD bibliography for
references. Only three references are listed that seem relevant to this
topic, but I may well have missed something so please let me know if there
are papers in the public domain I should be familiar with. I should also
note that I found a model included with Vensim that demonstrates the
adoption and diffusion of system dynamics as a very simple example growth
model.

de Rooij, A. (1992). Does system dynamics limit the growth of system
dynamics? In Jac A. M. Vennix, Jan Faber, Wim J. Scheper, & Cees A. Th.
Takkenberg (Ed.), Proceedings of the 1992 International System Dynamics
Conference of the System Dynamics Society (pp. 619-628). Utrecht, the
Netherlands: The System Dynamics Society.

Sterman, John D. (1985). The Growth of Knowledge: Testing a Theory of
Scientific Revolutions with a Formal Model. Technological Forecasting and
Social Change, 38(2), 93-122.

J. Wittenberg & John D. Sterman (1999). Path Dependence, Competition and
Succession in the Dynamics of Scientific Revolution. Organization Science.
10(3), 322-341.


I do not have access to the Proceedings of the 1992 conference to read the
first paper, so I am not at all sure if this paper does or does not contain
a policy model with the appropriate focus. I would be grateful if someone
could send me a copy of this paper. I read the last two papers and highly
recommend them. In his 1985 paper, John Sterman presents a model of Kuhns
Theory of Scientific Revolutions and the complete Dynamo model is provided
in the appendix. System dynamics is a new paradigm and therefore the
insights that emerge out of this model have implications for the life cycle
of our discipline/paradigm. The third paper by Wittenberg and Sterman
builds on and extends Johns 1985 paper, and explores the relative impact
of situational (environmental) factors during the birth of a paradigm
versus the intrinsic explanatory power of the paradigm. Again, this
version of the model yields insights that are relevant (even if somewhat
discouraging) for our paradigm. However, these models do not examine the
operational policies system dynamicists (or practitioners of any other
paradigm) may or may not adopt in managing the growth of our discipline.
In no way is this a criticism of the models; the models were simply
constructed for a different purpose.

My belief is that our community should develop a model with a focus on
testing various policies to manage the growth of our field. Ali presented
relevant pieces of stock and flow structure and the accompanying feedback
loops in his essay. I think this is a brilliant start, but we need to
formalize the analysis. Otherwise, our intuition about the dynamics of
this complex feedback system may be misguided. In my view, the modeling
project should strive to demonstrate best practice data collection and
model calibration given the data available, and should inform future policy
making of our society. Perhaps the conference in Palermo would be a good
venue to discuss this idea further and to gauge interest.

---
Shayne Gary
Australian Graduate School of Management
UNSW SYDNEY NSW 2052
Australia
Tel: +61 2 9931 9247
Fax: +61 2 9663 4672
Email: shayneg@agsm.edu.au
Web: http://www.agsm.edu.au