Measurement
ROAS (return on ad spend)
ROAS is revenue attributed to advertising divided by the spend that produced it, usually reported per campaign or channel.
The word doing the work is "attributed". Platform-reported ROAS uses the platform's own attribution model and its own view of which conversions it caused, which is why the sum of channel ROAS routinely exceeds total revenue.
It is also a revenue ratio, not a profit ratio. A 3x ROAS on a product with 30% contribution margin loses money. Break-even ROAS is the inverse of your contribution margin, and it is the number that should be on the dashboard.