Report on DFP placements
When you run reports on placements, it's important to keep these key concepts in mind.
The same ad unit can be in more than one placement
Placements can overlap, therefore total values for a group of placements could be higher than the total values for the ad units they contain. For example, if Placement A contains Ad Unit 1 and Ad Unit 2, and Placement B contains Ad Unit 2 and Ad Unit 3, a report on Placement A and Placement B includes data for Ad Unit 2 twice, because it's found in each placement.
Learn more about how to avoid double-counting report totals.
Placement reports reflect current ad unit associations
Report metric totals for the Placements dimension reflect the ad units currently associated with the placement. If you remove an ad unit, any reports run after that time will exclude the removed ad unit, even for dates before the ad unit was removed from the placement.
Since reports reflect current ad unit associations, you can report on placements for dates before you created the placement.
Yes. Before March 26, 2018, placement reports reflected historical ad units associations with a placement. Before this change, report metrics were only available for placements after their creation date.