Passive use value (also called non-use value) is the value that people place on the existence and preservation for future generations of a natural resource or a cultural asset* independent of any direct interaction that they may have with it.
Examples of such natural resources are iconic species (e.g., pandas and elephants), wilderness areas (e.g., the Amazon), biodiversity and beautiful scenery. Examples of cultural assets include historic cities and monuments (e.g., Venice and the Great Pyramids), artwork (e.g., the Mona Lisa), endangered languages, and original drafts of great books and music.
Passive use value contrasts with active use value, which, in the case of natural resources, comes from recreation and resource extraction activities, such as hiking, fishing, hunting, logging and mining. In the case of cultural assets, it can be the value derived from visiting them or viewing them in a museum.
Passive use value is an extremely large part of the value that humanity places on natural resources. In fact, in many cases it can greatly exceed the value derived from active use. However, this is often minimized, or even not considered, in public policy decisions, largely because it can be much easier and more convenient to just measure active use value, directly based on market transactions or inferred from actual use. The result can be suboptimal environmental protection legislation and enforcement.
Passive use value is typically measured using stated preference methods. The most common is the contingent valuation method, which utilizes carefully designed surveys to ask individuals questions such as how much they would be willing to pay to preserve or protect a resource even if they never personally use or visit it.
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* Theoretically, the concept of passive use value could extend beyond just environment and cultural assets, for example, the existence of facilities and institutions to care for less fortunate members of society, such as public housing and food banks. However, this is rare and appears to be little mentioned in the standard economic literature.