Sizing · The sanity check · Element
The comparator
Something observable the number can be checked against.
The part
What it is
A public competitor’s revenue, a known category leader’s share, a published industry figure. None is authoritative and all are useful as an order-of-magnitude check.
Where no comparator exists, that is itself informative about how well the market is understood.
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.