ROAS

Return on ad spend is revenue attributed to the ads divided by the money spent on them — a 4× ROAS means four rupees back for every rupee in. It is the retailer's version of cost per conversion, and it only means anything when the platform is told the value of each sale, which needs a tag that passes the order amount. Two things make a published ROAS unreliable: attribution, because the platform claims sales it merely touched; and margin, because a 3× return on a product with a 20% margin is a loss. A ROAS on a page with no account name and no window attached is a number to ask about, not to believe.