The Interactive Advertising Bureau (IAB) and the Media Rating Council (MRC) in partnership with other industry bodies such as the Mobile Marketing Association (MMA), periodically review and update industry standards for impression measurement. They recommend guidelines to standardize how impressions are counted across formats and platforms.
Over the last year, to remain consistent with these standards, we have transitioned our ad serving platforms from served impressions to downloaded impressions. Served impressions are counted at the point that we find an ad for an ad request on the server. Downloaded impressions are counted for each ad request once at least one of the returned ads has begun to load on the user’s device. Starting today, publishers will see updated metrics in AdSense that reflect this change.
How will it impact partners?
Switching to counting impressions on download helps to improve viewability rates, consistency across measurement providers, and aligns the impression metric better with advertiser value. For example, if an ad failed to download or if the user closed the tab before it arrived, it will no longer be counted as an impression. As a result, some AdSense users might see decreases in their impression counts, and corresponding improvements in their impression RPM, CTR, and other impression-based metrics. Your earnings, however, should not be impacted.
We will continue to review and update our impression counting technology as new industry standards are defined and implemented.
For more information please visit our Help Center.