Slippage · The ratio · Element
The split
How it varies by type of work.
The part
What it is
Familiar work slips less than unfamiliar work, and work with external dependencies slips most. Two or three categories are enough.
A single blended ratio over-buffers routine work and under-buffers the novel work that needs it.
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.