ExchangeWire opinion: data governance becomes core to ad measurement as identifiers fade

August 28, 2026 · ExchangeWire

Vishnu Vardhan Reddy Kaithapuram, a software engineer at Amazon Advertising writing in a personal capacity, lays out the shift in an ExchangeWire column published August 27. Chrome reversed its plan to remove third-party cookies and now leaves them active by default, and most of the measurement tools promised under Privacy Sandbox have wound down for low adoption. Identifiers eroded regardless: Safari and Firefox have blocked third-party cookies for years, Apple's tracking prompt hollowed out mobile identity, consent rates fell, and privacy law kept shifting. Kaithapuram, whose work centers on data governance and lineage, argues that advertiser analytics now runs on aggregation-first systems. Cohorts and time windows get fixed before data collection begins, and individual event rows never get joined back together after the fact. Conversion counts, he writes, arrive late and partly modeled, blending observed data with estimation for cases where consent or device tracking is missing.

Vendor conversations change shape once every reported number carries a paper trail. Kaithapuram suggests buyers ask how much of a figure was observed against how much was modeled, what the attribution window covers, whether totals restate as late conversions arrive, at what cohort size reporting stops, and whether noise has been added and disclosed. A vendor who answers those questions calmly is doing the work of governance. A vendor who treats them as rude is selling confidence as measurement. Planners who add this checklist to vendor reviews get a clearer read on which numbers to trust before they go into a media plan.