Sized before it is built.

Who to leave out is settled at the same moment as who to include. Where a rule rejects a row, the reason travels with the rejection. The handover includes what was removed, and why it was removed.

Intake review

Reading an existing file and reporting what is wrong with it before any work is proposed.

Null discipline

Keeping empty and unknown distinct, so a filter can tell the difference.

Scope agreement

Turning a written requirement into countable criteria, and confirming the size before any records are assembled.

Ask for the sample before the build. It costs nothing and settles most questions.