Download Systems Thinking and STELLA

the realities they represent. This leads to a very important statement
that will be repeated several times throughout this Guide. The
statement is a paraphrase of something W. Edwards Deming (the
father of the “Quality movement”) once uttered: “All models are
wrong, some models are useful.” It’s important to dredge this
hallowed truth back up into consciousness from time to time to prevent
yourself from becoming “too attached” to one of your mental models.
Nevertheless, despite the fact that all models are wrong, you have no
choice but to use them—no choice that is, if you are going to think. If
you wish to employ non-rational means (like gut feel and intuition) in
order to arrive at a conclusion or a decision, no mental model is
needed. But, if you want to think…you can’t do so without a mental
model!
Figure 1-1 presents a STELLA map of the activities that comprise
“thinking:” constructing (a mental model), and simulating in order to
draw conclusions. As the Figure indicates, constructing is divided into
two sub-activities: selecting and representing. The first sub-activity
answers the question: What should I include in my mental model? The
second sub-activity answers the question: How should I represent what
I include? These are the two fundamental questions that must be
answered in constructing any mental model. It is my conviction that
the paradigms currently governing teaching in our schools restrict
development of the whole set of skills needed to become effective in
executing both the constructing and simulating activities. That is, our
schools are thwarting development of thinking capacity—something
no school board would approve, and we can ill afford!
Constructing
All Possible
Elements
selecting
Elements Included in the
Mental Model
Represented Elements
in the Mental Model
representing
Simulation
Outcomes
simulating
Simulating
Conclusions
& Decisions
Figure 1-1.
A STELLA Picture of “Thinking.”
drawing\making
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