Public goods

Public goods are a core concept in economics, describing goods available to all members of society and usually funded collectively. They're defined by two features, non rivalry, where one person's use doesn't diminish another's and non excludability, meaning it's difficult to prevent anyone from accessing them. Examples include national defense and street lighting, goods that serve everyone regardless of payment, making them central to debates about government provision and market efficiency. Understanding non rivalry and non excludability clarifies why public goods require distinct economic treatment. Non rival goods like sunlight, can be enjoyed by many with no additional cost for extra users, unlike rival goods such as bread, which can only be consumed once. Non excludable goods are those from which people cannot easily be prevented from benefiting, such as street lighting, where everyone benefits without paying. This characteristic makes it hard for private markets to supply public goods efficiently, often requiring government or collective action. A major challenge posed by public goods is the free rider problem because people cannot be easily excluded and it costs little or nothing for extra people to benefit. Some individuals may choose not to pay, expecting that others contributions will maintain the good. When everyone follows this logic, the public good is underfunded or not provided at all. Governments frequently address this problem through taxation and collective decision making. Sometimes approaches like club goods,