Index Crest

Checked against the source, not assumed.

An audience is described, agreed, and only then assembled. Suppression is applied at the start, so the approved figure is the delivered figure. Each delivery says how old its parts are.

Suppression

Exclusion lists applied properly, so a record you asked to withhold stays withheld.

Null discipline

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

Seed insertion

Placing known addresses in the file so you can see for yourself what was sent and when.

Ask for a sample first. It is the quickest way to find out whether this is useful.