Cross-device location stitching

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Location histories merged across a household's or individual's multiple devices via probabilistic ID-graph stitching can double-count visits or attribute one device's location to another device incorrectly, inflating cell-level audience counts.

Detection

Same physical visit event appears against more than one device ID in the graph within an implausibly short time window (e.g. same location, same minute, two device IDs).

Mitigation

Deduplicate at the household/individual (stitched) level before cell aggregation, not at raw device level
Track and report the ID-graph match confidence tier alongside any cross-device audience count

Affected conversions

Point → H3 exact