Measuring perception · The limits · Element
The not reached
Who is missing from the sample.
The part
What it is
Lapsed customers, people who considered and chose otherwise, and anyone who declines to participate in research are the three groups most often absent.
They are also the three groups most likely to hold the unflattering view, which makes their absence systematic rather than random.
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.