Let the question determine what to model

Begin with an episode, proposal or unexplained result. Ask who needs an answer, what they could do with it and which difference would change that action. Obtain relevant participants’ accounts where possible; otherwise use attributable interviews, documents and observations, retaining unanswered questions for those who know the work. Participation in constructing the model can help correct it, but attendance does not establish agreement with a proposal.

Consider a car park whose unreliable sensors sometimes send drivers towards occupied floors. Attendants walk the floors and correct the displayed counts. Management proposes replacing the entire system, since the sensors cannot simply be exchanged in the current design. The initial inquiry is: does replacement address the service difficulty better than continuing manual correction? This is an adaptation of the parking exercise in the iStar tutorial, slide 57. The following participants, conditions and judgements are constructed for this walkthrough.

Include drivers because the guidance affects finding a place; attendants because correction requires their work; the operations manager because staffing and service arrangements are theirs to decide; and the technical supplier because replacement feasibility and installation depend on its contribution. Management cares about operating cost and reputation. Drivers care about usable guidance and protection of their cars. An attendant’s account of an assignment is evidence about that work, not a statement of every driver’s preferences.

Keep the questions distinct. What would make the displayed count trustworthy? Can the work supply it when needed? How would the alternatives affect cost and the concerns behind reputation? A model of intentions can expose these questions before it has the technical estimates needed to answer all of them.