Google Ditches Count-on-Download Ad Impression Metric
Google is making a significant change to how it counts display ad impressions. Starting February 17, 2027, ads will only be counted as impressions once they have finished loading and started rendering on screen.
This means that slow-loading ads that never appear to the user will no longer be included in impression counts. The current system, known as Count-on-Download (COD), records an impression as soon as the creative begins downloading, regardless of whether it ever appears.
The change, which affects both AdSense and Ad Manager platforms, is expected to result in a decline in reported display impressions. This could have implications for publishers who rely on raw impression totals for revenue planning.
Eytan Sayag, a guest columnist at MarTech360, warned that the update could lead to a drop in ad revenue for sites not technically prepared for the change.