Return on investment

Return on investment (ROI) is a performance measure used to evaluate the efficiency of a project or to compare the efficiency of a number of different projects. ROI measures the amount of return on a project relative to its cost. To calculate ROI, the return (net benefit: benefit minus cost) of a project is divided by the cost of the project, with the result expressed as a percentage. The requirement of benefit to be expressed in money terms is the main reason that ROI (or cost-benefit analysis) is not used extensively in health technology assessment; however, it is used in other contexts such as planning large capital investments (new hospitals, units or services). It is important to note that using ROI in isolation can result in inefficient decisions. For example, just because an intervention has a positive ROI does not necessarily mean that it has the best ROI of all available options. The percentage ROI value does not give an indication about affordability.