Return on Ad Spend (ROAS) is the revenue generated from each pound spent on advertising. It is a key measure of a campaign’s profitability: a ROAS of 4 means £4 of revenue for £1 spent on advertising. Note: ROAS counts revenue, not profit. It does not account for margin or other costs, so a high ROAS does not always mean the business is earning (that is what ROI is for). (Compare: ROI, ERS)