Glossary
What is Temporary CPM?
Also called: opportunity cost CPM
A temporary CPM is the opportunity-cost price Google Ad Manager gives a guaranteed line item so Ad Exchange can compete with it.
हिंदी में पढ़ेंGuaranteed line items (Sponsorship and Standard) are not sold on price per impression, so Ad Manager needs a number to compare them with Ad Exchange bids. It calculates a temporary CPM automatically, representing the opportunity cost of not serving the campaign on this impression.
The temporary CPM moves with delivery. When a campaign is on pace, its temporary CPM stays low enough for higher AdX bids to win some impressions. When it falls behind, Ad Manager raises the temporary CPM, so the line item wins more often and finishes on time.
You do not set the temporary CPM yourself, and remnant line items at priority 12 do not get one. They compete on their rate, or on a value CPM if one is set. If AdX seems to be taking impressions from a guaranteed campaign, check its pacing first: on pace means the system is working as designed.
Example
A Standard line item is on pace and gets a $4.00 temporary CPM. AdX bids $6.00, so AdX serves. Later the campaign falls behind and its temporary CPM rises to $7.00, so it beats the next $6.00 AdX bid.
Why it matters to publishers
The temporary CPM explains why AdX sometimes wins impressions from your guaranteed campaigns, and why pacing is the thing to check.