Data briefs
Preparation, rather than procurement.
The first pass is deliberately narrow, and widened only on request. A sample is pulled and read before the full run is committed. Columns without a written meaning are left out rather than shipped undocumented.
Address normalisation
Standardising location data before comparison, so one place does not read as several.
Mailbox shape
Distinguishing an individual's address from a shared or departmental one before either is used.
Matching
Reconciling what you hold against what is current, with disagreements surfaced rather than silently resolved.