Qualifying · The questions · Element
The set
What is asked.
The part
What it is
What would make this not worth doing; whether we could actually deliver it; what it displaces; and how long it is available.
Four questions, answerable by making three phone calls.
The smallest level
The attributes it carries
Each attribute is one of the framework’s shared types. What a date is, and how it is written, is defined once for the whole model — the note here says what it means in this particular place.