Where the money died
Every delivering ad, stage by stage: link clicks charged for, landing-page views that actually arrived, checkouts started, purchases. The biggest drop is where the money goes.
The offer, as the buyer meets it
Daily spend and return
Top by spend
Spend against creative volume
When spend climbs and the number of new creatives does not, the return follows the creative line down. This is the ratio to protect during a scale-up.