lapse-and-winback

This skill answers one question: who counts as lapsed, how to notice somebody leaving before they have gone, and what one finite attempt to bring them back looks like.

The churn metric itself is metric-definitions. The engagement tier and how often the dormant tier gets mailed inside the standing program is email-program. The silence threshold that takes a record out of the active base is list-building. What lives here is the deliberate attempt: it has a population, a start, a declared end, and an outcome for everybody who entered it.

Lapse breaks quietly, and in the opposite direction from everything else in the program. The rest of a program is visible through sends: something went out, something got opened. Leaving produces no event at all. The person stops appearing, and the only trace they leave is the absence of a trace. A campaign report does not show it, because a campaign report counts the people who received something, and by the time anybody reviews it the lapsed are not on the list.