Marketing
ROAS
Return on ad spend, as the platform counts it.
Formula
Attributed revenue ÷ ad spend
ROAS is return on ad spend: attributed revenue divided by spend, reported by the advertising platform itself. Because every platform claims every conversion it can plausibly see, the same order is often counted by two or three of them, which makes platform ROAS unusable as a single source of truth.
That is not fraud, it is what attribution windows do. Each platform answers honestly from inside its own window, and the windows overlap, so the sum of everyone's claimed revenue is routinely more than the store took.
Keep it, but demote it: it is a relative signal for comparing two creatives inside one account on one day, and nothing more. The moment it is used to judge the whole budget, the overlap starts flattering whichever platform claims fastest, and that race is structural rather than a settings problem.
The blended alternatives, and when each one is the right tool, are set out in MER, POAS or ROAS.