A calculation of the monetary value of an investment versus its cost. The mathematical formula is: (profit minus cost) / cost. If you made $10,000 from a $1,000 effort, your return on investment (ROI) would be 0.9, or 90%. ROI is often used to evaluate business strategy, including all advertising and marketing efforts. Return on ad spend (ROAS) is a similar metric, but it focuses more on specific tactics, such as an individual ad campaign.
Whether you choose to do your marketing online or offline, one thing does not change. This is the concept that no single marketing strategy will be as effective as a combination of two or more marketing strategies.