The mix · The interactions · Element
The cannibalisation
Where one channel takes credit or volume from another.
The part
What it is
Retargeting and branded search are the common examples: both reach people who were already coming, and both report well for that reason.
The test is a holdout, and the finding is frequently that a well-performing channel is adding much less than reported.
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.