Scope agreed before anything gets built.
A build begins with the question nobody enjoys: who is excluded? Where two sources disagree, the conflict is recorded rather than resolved silently. Every claim the file makes about itself can be checked against it.
Threshold disclosure
Naming the cut-off used wherever a judgement was made on a score.
Validation
Checking structure and reachability before a file is used, not after.
Overlap reporting
Where segments share records, stated rather than double-counted into a bigger total.
If it turns out your existing data is fine, that is a perfectly good outcome.