First/Last Touch Property

A first/last touch property is a user attribute that holds its value from the user's first (or last) contact — for example the first channel the user arrived from.

This kind of property answers an attribution question: should a user's or a conversion's credit go to the first acquaintance or the last. A first-touch property stays fixed even if the user later returns ten more times, so it helps understand which channel discovers the audience; a last-touch property updates on each visit and credits the channel that brings the user back to act. Building such a property needs two things that are not always available: a stable user identity over time, and logic that locks the first value and replaces the last. The common trap is that a team thinks it holds the true first touch when it only holds the first trackable one; if the user's very first visit had its signal erased and sat in Direct, the recorded first touch is the second channel, not truly the first.