Unity & In-App UA
eCPM
Effective cost per mille — revenue or cost per thousand impressions after normalizing across formats and pricing models, the common yardstick for comparing in-app inventory.
eCPM lets you compare unlike things on one scale: a rewarded placement priced on completions and an interstitial priced on installs both resolve to a cost per thousand impressions. For a buyer it is a read on how expensive a given inventory pocket really is once the pricing model is stripped away.
Watching eCPM by GEO and format tells you where attention is cheap and where competition has bid it up. The trap is optimizing eCPM in isolation: cheap impressions that never install are not a win, so eCPM is a lens on cost, not a goal on its own.
In buyer speech
“eCPM on that GEO doubled during the tournament, so we shifted budget to the formats that still cleared our cost per install.”