cost benefit analysis
Cost benefit analysis is the method for determining whether a particular project or policy is socially worthwhile. The positive impacts are reduced to their monetary equivalents and discounted back to the base time. The sum is these values is called the social benefits of the project. The corresponding negative impacts lead to the social costs of the projects. If the social benefits exceed the social costs the project is socially worthwhile.
The site provides the theory and examples of cost benefit analysis.