Milestones · The milestone schedule · Element
Slippage
How each date has moved since it was first set.
The part
What it is
A date that has moved three times has stopped being a plan. Recording the movement is what makes that visible before the final date arrives.
It also distinguishes a project that is late from one that was estimated wrongly at the start, which call for different responses.
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.