Pooled location sources in delivery logs

advertising

Bid-stream location carries a per-impression provenance flag (e.g. OpenRTB device.geo.type: GPS vs IP-derived vs user-declared), but delivery logs are routinely aggregated across it, pooling a tight error distribution with a wide one and hiding the displacement that segmenting would reveal for free.

Detection

Delivered-cell distributions of GPS-sourced and IP-sourced impressions in the same market and window diverge materially when segmented.

Mitigation

Preserve the location-source flag through logging and aggregation
Report delivered-cell distributions per source class as a standing delivery-quality diagnostic
Treat the GPS-vs-IP divergence as a per-campaign bound on IP displacement — noting the consented-GPS subset is small and skewed, so it bounds rather than measures

Affected conversions

Point → H3 exact
IP lookup → H3 (probabilistic crosswalk) approximate