Cross-Device Tracking Explained: Why It’s Hard
Cross-device tracking tries to connect interactions from the same person across multiple devices. It is difficult because devices do not automatically share a stable identity.
Why device changes break journeys
A click on a phone and a purchase on a laptop can appear to be two unrelated users unless a system has a reliable way to connect them.
Deterministic matching
Logged-in account data or another stable first-party identifier can sometimes connect devices with stronger confidence.
Probabilistic methods
Some systems infer matches from patterns or signals, but inference introduces uncertainty and privacy considerations.
Attribution implications
If a system cannot connect devices, the final conversion may be credited to a later touchpoint or appear unattributed.
Focus on business decisions
The goal is not omniscience. Measure whether the remaining gaps materially change campaign decisions.