Nonexcludable benefits, nonrival use, free riders, collective action, government provision, public health, national defense, streetlights, and global commons
Public goods
Public goods are goods or services that people cannot easily be excluded from using and whose use by one person does not greatly reduce use by others. They help explain why markets may underprovide some valuable shared benefits.
What public goods are
In economics, a public good is defined by how people can use it, not simply by whether a government pays for it. A pure public good is hard to exclude people from and can be used by many people at the same time without being used up.
Nonexcludable
A good is nonexcludable when it is difficult or costly to prevent someone from benefiting once the good exists. A lighthouse, disease surveillance system, or clean air rule may help people who did not directly pay for it.
Nonrival
A good is nonrival when one person's use does not significantly reduce another person's ability to use it. One person benefiting from a streetlight or weather forecast does not usually make it unavailable to someone else.
The free rider problem
Because people can benefit without paying, private firms may find it hard to sell enough access to cover costs. This free rider problem can lead markets to provide too little of a public good, even when society values it highly.
Public provision and funding
Governments often provide or fund public goods through taxes, grants, public agencies, prizes, or contracts. Communities, nonprofits, and international institutions can also help organize provision when benefits are shared widely.
Not every public service is a public good
Some services funded by government are not pure public goods. A crowded road, hospital bed, or classroom seat can be rival, and tolls, fees, or eligibility rules can make some services excludable.
Why it matters
Public goods explain debates about defense, public health, climate stability, open data, scientific research, disaster warning systems, biodiversity, and basic infrastructure. They show why private incentives may not match shared needs.
Global public goods
Some public goods cross borders, such as pandemic preparedness, financial stability, climate protection, and knowledge. These are harder to provide because countries may disagree about responsibility, cost sharing, enforcement, and fairness.