Margin structure · The cost to serve model · Element
The allocation basis
How shared costs are attributed, and what that choice does to the answer.
The part
What it is
Allocation basis determines the conclusion. Allocating by revenue makes large customers look expensive; allocating by activity makes demanding ones look expensive.
Stating the basis is what makes the model arguable, which is the property a costing model most needs.
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.