Prior to early 2016, ad impressions counted each text ad in an ad slot as an Ad impression. We're changing this behavior to only count the ad slot once, deprecating the prior definition of Ad eCPM (legacy), and adding Ad eCPM. Here is the summary of changes:
|What's changing?||Before||After||What to expect|
|Name of eCPM for matched impressions||eCPM||Matched eCPM||Only a change in eCPM label for improved clarity. The eCPM values don't change.|
|New Ad eCPM and Ad Impressions||None||
Ad slots containing multiple text ads will be counted as a single ad impression, whereas today each ad is counted individually.
For example, previously if a ad slot served 2 text ads to a single slot, it would count as 2 ad impressions - both for the ad impression metric and in the denominator of Ad eCPM. With this change, only a single ad impression is counted.
|Default eCPM||[Matched] eCPM||Ad eCPM NEW||Default eCPM shown in reports, home page, and system reports will become the new Ad eCPM metric. You can always choose to include Matched eCPM or Ad eCPM metrics in your report.|
|Deprecation of the old definition of Ad eCPM and Ad Impression over time||
Publishers will initially be able to access the historical data via the deprecated metric. Over time these legacy metrics will be removed.