Tracking
Signal loss
Decline in measurable user data due to privacy changes.
Signal loss is the umbrella for the decline in measurable user-data driven by post-2020 privacy changes: Apple ATT (iOS 14.5+, 2021), Safari ITP, Firefox ETP, Chrome cookie deprecation. Net effect: ~30–60% reduction in conversion-attribution accuracy across most direct-response channels since 2021. Mitigations: CAPI (Meta), Enhanced Conversions (Google), GA4 modeling, server-side tracking, MMM (media-mix modeling) for triangulation.
Example
DTC brand running Meta + Google saw measured ROAS drop from 4.2× to 2.7× post-iOS 14.5 — actual ROAS unchanged, signal loss accounted for the gap. Implementing CAPI and Enhanced Conversions recovered ~70% of the lost attribution.