Stands for 'Return on Advertising Spend' and is used to determine media effectiveness. It is the amount of revenue generated for every dollar spent on advertising. For instance, a ROAS of $1 means you're generating $1 in sales for every $1 in advertising spend, and a ROAS of $5 means you generate $5 in sales for every $1 in advertising spend.
This can also be represented as 5:1 or 16:1 meaning that for every $1.00 spent you get a return of $5.00 or $16.00.
To learn more about ROAS visit our comprehensive blog post.