Cross-device User
Intermediate PronunciationEN/krɔːs dɪˈvaɪs ˈjuːzər/
A cross-device user is one person who reaches the same product from more than one device and therefore carries more than one anonymous identifier.
Until the person signs in there is no reliable way to join those identifiers; the sign-in moment is the only point where a system can state with confidence that two identifiers are one person. The consequence shows in every device-split report: it is a split of devices, not of people. The most common wrong conclusion is comparing mobile and desktop conversion rates and declaring mobile weak, when in many products the browsing and comparison happen on a phone while the final purchase is recorded on a desktop, so the whole value of the mobile journey is credited elsewhere.