Skill levels in system dynamics

[jforestr@MIT.EDU (Jay W. Forrest]

REPLY to: Differential equations (SD0910) From:Bill Harris

>Some on this list seem to
>have argued in favor of SD being practiced only after serious study in a
>university program (at the graduate level?) with the opportunity for the
>prospective SD person to receive feedback on their modeling efforts. I can
>see the benefits of such study. Some in the SD community (vendors,
>perhaps?) seem to suggest the "democratic notion" that SD can be done
>relatively easily by using todays tools and the admittedly good manuals
>they provide.
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I often liken system dynamics to the profession of medicine. There is a
continuum of skills from a person having attended a two-hour first-aid
course to one who has the skill to do a heart transplant. The issue is not
so much the level of skill as the recognition of the skill one has and the
willingness to work within the boundaries of that skill level, even while
increasing the skill. My major concern here is with those who attend a
rather superficial three-day "systems thinking" conference and then propose
that they are ready to be consultants on major corporate system dynamics
challenges.
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>How concerned are you about the work someone does who is working through
>the Road Maps and using SD in a practical sense? What risks do you see in
>the conclusions they may be drawing which they should take special pains to
>avoid? Must those risks be ameliorated through undergraduate or graduate
>courses, or is there another way?
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System dynamics skill should be considered in the context of skills based
on mental models alone because todays decisions come almost exclusively
from mental models. Is system dynamics modeling (at any level of skill) in
danger of making the decisions based only on mental models worse? I doubt
it. The thought that goes into making even a poor system dynamics model
will probably sharpen up the mental models. If the mental models that will
otherwise be used are so bad that they can not benefit by some modeling,
they probably can not be made worse even by very unskilled SD modeling.
Having said that, it is important to keep in mind that small increments of
improved thinking via elementary modeling will fail to achieve the factor
of ten or a hundred in outcomes that might be achieved by the best modeling
practice. Going back to medicine, system dynamics is probably now in about
the state of development that medicine was a century ago. So, do the best
we can today, dont think it is the ultimate, and keep the door open to
learning in all ways that are possible.
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>I recognize I wouldnt presume to teach myself a
>skill such as playing a musical instrument, for example, without a private
>teacher unless it were purely for fun... These may be primarily
>characteristics of physical activities, though.
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No, not just physical activities. An engineer is not prepared for the most
demanding work in the field on graduating from college. Practice,
apprenticeship, and experience are necessary. Likewise in system dynamics.

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Jay W. Forrester
Professor of Management, Emeritus
and Senior Lecturer, Sloan School
Massachusetts Institute of Technology
Room E60-389
Cambridge, MA 02139
tel: 617-253-1571
fax: 617-252-1998

email: jforestr@mit.edu