First the universe is defined, then it is measured, then it is built. Where a rule rejects a row, the reason travels with the rejection. Coverage is reported as three numbers: matched, unmatched, and unverifiable.
Correction
Updating what has changed, wherever a current value can be established.
Entity resolution
Collapsing several records describing one organisation into a single row, with the reasoning kept rather than discarded.
Field provenance
Keeping the origin and date of each value with the record instead of flattening it away on delivery.
Send the requirement in whatever form you have it and we will shape it into criteria.