In cost–benefit analysis and social welfare economics, the term option value refers to the value that is placed on private willingness to pay for maintaining or preserving a public asset or service even if there is little or no likelihood of the individual actually ever using it. The concept is most commonly used in public policy assessment to justify continuing investment in parks, wildlife refuges and land conservation, as well as rail transportation facilities and services. It is also recognized as an element of the total economic value of environmental resources.