nonrivalrous

Nonrivalrous describes a good or service for which one person’s consumption does not reduce the amount available to others. In other words, the marginal cost of serving an additional user is zero or negligible, so many consumers can be served simultaneously without crowding out others. This property is used with excludability to categorize goods.

Public goods are commonly defined as non-rivalrous and non-excludable; other categories include club goods (excludable but non-rivalrous up to capacity), common-pool resources (non-excludable but rivalrous), and private goods (both rivalrous and excludable).

Examples include digital information, open-source software, and broadcast signals or online content that can be consumed by many without diminishing supply. In practice, bandwidth and other constraints can make some otherwise nonrivalrous goods rivalrous at scale.

Economic implications include free-rider problems and potential under-provision if access cannot be efficiently charged. Nonrivalry supports scalable provisioning but also complicates pricing and incentives; governments or institutions often fund or license such goods, while ensuring some form of access control or stewardship.

The concept dates to public economics, with Paul Samuelson’s work in the mid-20th century helping to formalize the link between non-rivalry and the notion of public goods. The term remains central to discussions of information goods, digital services, and other resources whose use by one person does not necessarily diminish use by others.