Fewer rows, better ones.
Scope is settled in advance so the size is never a surprise. Formatting is settled early, because reworking a delivered file costs more than preparing it. Coverage is reported as three numbers: matched, unmatched, and unverifiable.
Delta reporting
On a refresh, naming the records that joined, left or changed since the last version.
Classification check
Verifying categories against the underlying description rather than trusting a label applied upstream.
Known-gap register
A written list of what the file does not contain, kept with the file.
If mail is not arriving, we will look at the configuration and say what we find.