SD a special case of Complexity/Chaos?

This forum contains all archives from the SD Mailing list (go to http://www.systemdynamics.org/forum/ for more information). This is here as a read-only resource, please post any SD related questions to the SD Discussion forum.
Locked
Tom Fiddaman
Junior Member
Posts: 10
Joined: Fri Mar 29, 2002 3:39 am

SD a special case of Complexity/Chaos?

Post by Tom Fiddaman »

John -

Great question you passed along.

>QUOTE
>I have seen some significant critiques of SD as THE answer from some of the
>Complexity and Chaos texts.

Id be really interested to know WHICH Complexity and Chaos texts were
talking about. I think its incredibly important to think about the
limitations of SD, especially with respect to the type of training and R&D
we should be pursuing in the field.

>Again I am at the limits of my knowledge here,
>but I think they regard SD as a special case of a more general
>methodological approach.

I would agree that the models that fall under the Complexity and Chaos
heading are a superset of normal SD practice. Discrete-time chaos, genetic
algorithms, and detailed disaggregation of agents or spatial dimensions are
common Complexity topics that are not often part of SD work. To the extent
that we can keep aware of these areas, and blend them with our work, I think
we benefit (though discrete time chaos seems pretty useless to me).

At the same time, I dont see much of a coherent problem-solving methodology
in complexity and chaos research. SD, by contrast, has well-developed
traditions for eliciting knowledge from stakeholders, building and testing
models, and communicating or implementing results. SD also has a fairly
strong set of principles for the appropriate representation of behavior. In
applications of complexity research I too often see genetic algorithms used
as a model of behavior, without empirical justification, where Occams Razor
might suggest a simple hill-climbing process instead.

Some of the management literature Ive seen makes appealing metaphorical use
the insights that come from complexity research. However, when you try to
actually tie down assertions about management principles to modeling
particulars, you find nothing but rubbish. I know several colleagues who
could go on at greater length about this. The same can be said of some
management allusions to quantum physics, which sometimes seem to me to imply
that, because Schrodingers cat can exist in multiple states, I can step in
front of a speeding bus without being killed.

This is damaging to all modeling disciplines; it erodes our hard-won
credibility by using pseudoscience as a bogus source of authority. If the
espoused management principles are really worthwhile, then it should be
possible to demonstrate them explicitly and subject them to formal criticism.

As always the problem is then to identify the
>special circumstance.

Id venture to say that the special circumstance is exactly the areas in
which SD is thriving, especially modeling the dynamics of particular
businesses or public organizations. It might be easier to identify areas in
which SD is infrequently applied or has trouble making an impact. Ill leave
that thought dangling for the next taker.

- Tom



****************************************************
Thomas Fiddaman, Ph.D.
Ventana Systems
http://www.vensim.com
34025 Mann Road Tel (360) 793-0903
Sultan, WA 98294 Fax (360) 793-2911
http://home1.gte.net/tomfid/ tomfid@premier1.net
****************************************************
Locked