Exclusion handling
An audience described, then measured.
The brief is the specification, and it is written before the build. Categories are checked against the underlying description, not the label attached upstream. What arrives is a file whose every column has a written definition.
Classification check
Verifying categories against the underlying description rather than trusting a label applied upstream.
Sending identity
Separating what you send in volume from how your main domain is treated.
Null discipline
Keeping empty and unknown distinct, so a filter can tell the difference.