Public goods

Public goods are non-excludable and non-rival: people cannot readily be prevented from using them, and one person’s use does not reduce availability to others. These traits can make private provision unprofitable.

Non-excludability: A property of a good or service that makes preventing access difficult or costly. It lets people benefit without paying, weakening providers’ ability to recover costs.
National defense: The organized protection of a state and its population against external threats. Protection is broadly shared and difficult to withhold from residents who do not pay individually.
Private good: A good that is both excludable and rival in consumption. It contrasts with public goods on both defining dimensions.
Government provision: The direct supply of goods or services by public authorities. Tax funding can address the difficulty of charging each beneficiary voluntarily.
Global public good: A good whose benefits extend across countries, populations, and generations. Climate stability and disease control raise provision problems beyond any single government’s jurisdiction.
Non-rivalry: A property of consumption in which one person’s use does not reduce what remains for others. An additional user can benefit without consuming a scarce unit another person needs.
Street lighting: Illumination of streets and public spaces using installed lights. Its benefits reach many passersby, while excluding non-payers from the light is impractical.
Club good: A good that is excludable but largely non-rival until congestion occurs. Membership or access controls can prevent free riding despite shared use.
Public finance: The study and practice of government revenue, spending, and debt. It examines how collective goods are funded and how their costs are distributed.
Climate change mitigation: Actions that reduce greenhouse-gas emissions or increase their removal from the atmosphere. Each country benefits from others’ reductions, complicating cooperative provision of climate stability.

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