This is a measure of the amount of money made (Return) for a given amount of money invested (Investment).
Academic ROI is a translation of this concept into the education world as a way to measure the amount of academic outcome achieved for a given amount of investment made.
The Academic Return on Investment (Academic ROI) can be measured as the amount of learning or other educational outcome achieved per dollar spent on a school product or service; in the true vernacular, "Bang for the Buck."