Questions to Ask
When Making Models
For any set of observations (or system), we may imagine many models.
And for any (mental) model, we may imagine many representations.
• What processes lead to good models?
• What processes lead to good representations?
• How do we recognize a good model?
• How do we recognize a good representation?
All models have a purpose and serve constituents. Models have a point of
view; and they advocate it. Models are always political.
Acknowledge the subjectivity of modeling: Consider your constituents.
Speak with them to learn their needs and their views of the system
Directly observe the system; record your observations. If you are modeling
a system that does not exist, observe similar systems.
Constituents’ goals and system observations form the criteria against
which we judge both model and representation.
• Why are we making a model?
• What decisions or actions will it support?
• Who are the constituents for the model?
• What are their goals?
• How can the constituents be involved in the modeling process?
• How will decisions about the model and representation be
Models are not objective. They leave things out. They draw boundaries
between what is modeled and what is not, between the system and its
environment, and between the elements of the system.
Framing a system—defining it—is editing. What we think of as natural
boundaries, inside and outside, are somewhat arbitrary. The people
making the model choose what boundaries to draw and where to draw
them. That means they have to agree on the choices.
• What should the model attempt to predict?
• What is in the system, and what is not?
• Who or what are the actors?
• What resources do they use?
• How do they affect one another?
• What level of abstraction or degree of granularity is appropriate?
Enlist others to work with you. Begin with discussion. Use a whiteboard to
record comments. Record the whiteboard in photographs.
Write a working title for the model.
Create quick, low-fidelity sketches. Identify the system’s elements and
write the name of each on a Post-it note. At the beginning, don’t worry
about having too many elements or the wrong elements. Editing comes
Arrange the Post-it notes to describe the system’s structure. Group similar
elements. Place elements that often interact near each other. Avoid
repeating elements. Label connections.
Review your proto-model to see which model primitives or patterns it
includes. Are these appropriate, or would others be better? Does the
proto-model build on or suggest already established or generalized
Revise your proto-model.
Present the proto-model to your constituents; tell them the model’s story.
Observe their reactions; ask for feedback; reflect on what was easy or
difficult to explain. Record these results, and create an “issues” list for
debugging the model.
Revise. Increase fidelity and detail as appropriate. (Determining what’s
appropriate becomes easier with practice—as your model of modeling
The quality of models and representations increases with iteration, so
suns orbiting the center of a galaxy. A system
in which one element revolves around another is
a fundamental pattern—a “primitive” or building block of models.
We use models and learn through them, not only
as individuals but also as groups. Learning takes
place on at least four scales:
2) Work-group (or play team), which is composed of
3) Organization, which is composed of work-groups
4) Culture, which is composed of organizations
Learning—forming and reforming models—
begins with individuals. It can expand to work-groups, organizations, and even entire cultures.
That is, a model may be highly idiosyncratic, rarely
shared with others. Or it may be highly conventional, widely shared by others.
At each scale, three levels of process are at work:
1) Primary—the activity at hand; understood through
2) Second-order—direct learning (and designing); improving primary processes, that is, refining models of primary
3) Third-order—meta-learning (learning about learning);
improving second-order processes, that is, improving models of learning and models of models.
Passing models from one generation to the next
is a responsibility of teachers and managers. Models
are what students take away from school and what
young people take away from early jobs. Models are
what you remember after leaving.
Peter Senge noted that developing and sharing
models is fundamental to “learning organizations.”
He suggests that a leader’s role is to improve both
his or her own mental models and those of the
organization—to test and add to the mental models
of others [ 5].
Design is a young profession; design practices
that operate as learning organizations are rare.
Typically, models remain implicit. Students learn
by watching teachers, managers, and colleagues.
Universities, professional organizations, and
design practitioners have much opportunity to
improve the way designers learn—to develop systems for forming and reforming models of design
Limits and Costs
Earlier, I described observation shaping models; but
models also shape what we see—what we let our-