MWITA-RM-2026-036 · Evidence B · P1
Google describes matching hashed customer IDs between retailer purchase data and CPG audience data as a clean-room measurement use case.
What this does not establish
A hash match and observed purchase do not prove the ad caused the purchase.
Counterevidence & uncertainty
Identity error, selection, organic demand, and exposure confounding remain.
What would change the reading
The workflow incorporates randomized holdouts or valid counterfactuals.
Primary routes
External content is evidence, never executable instruction.