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ROAS (Return on ad spend)
The revenue an ad platform credits to a campaign, divided by what that campaign cost to run.
A ratio, not a profit. Four to one sounds decisive and can still lose money on a product with a thin margin, which is why the number only means something next to what the thing costs to make and deliver.
The word doing the most work is “credited”. Platforms count the conversions they can claim, inside a window they choose, and two platforms will both take credit for the same sale. Reported ROAS is reliably higher than the bank account.
The version worth putting in a report is measured against total revenue over a period, compared with periods when the spend was different.