Geographic information systems (GIS) are in widespread use by both public and private organizations. Many more organizations would like to implement the technology, but they must first justify this major purchase. The most commonly used technique to justify any capital investment (including GIS) is costbenefit analysis (sometimes called benefit-cost analysis). Cost-benefit analysis is just what its name implies: a balance sheet for a capital expenditure that includes costs on one side and benefits on the other, along with a comparison of the economic (dollar) value of each. This entry presents the basic elements of cost-benefit analysis, providing examples of specific benefits and costs associated with GIS implementation. The entry also discusses enhancements to basic cost-benefit analysis with the addition of a discussion of discounting. Finally, ...