Gathering it · The instrument · Element
The length
How much is asked.
The part
What it is
Short enough that completion is high, since a long instrument selects for the people with strong views and time.
Three questions completed by most people beats fifteen completed by few.
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.