List penetration tells you how far a campaign has gone through its data.
List penetration = contacts worked at least once ÷ total contacts in the list × 100
A list of 10,000 contacts with 6,500 worked is at 65% penetration. Teams often track a second figure alongside it: how many contacts are closed, either with a final disposition or because they reached the maximum number of attempts. A list can be 100% penetrated and still have many contacts left to retry.
Penetration helps decide when to add fresh data, when to recycle a list and when a list is simply poor. Read it together with the connect rate and conversions per list: a list with high penetration and few conversions is a candidate to retire.
In OVOKY, a campaign can mix several lists evenly, by weight or by priority, and the list penetration report in reports shows coverage per list with a breakdown by disposition.