Public Economics
Public economics studies the role of government in the economy — how taxation, public spending, and regulation affect efficiency and equity, and how to correct market failures and provide public goods.
Scope
The field (JEL category H) covers public goods, externalities, taxation and optimal tax theory, public expenditure and social insurance, fiscal federalism, and public choice, combining welfare economics with empirical analysis of policy.
Sub-topics
- General
- Structure and Scope of Government
- Taxation, Subsidies, and Revenue
- Fiscal Policies and Behavior of Economic Agents
- Publicly Provided Goods
- National Government Expenditures and Related Policies
- National Budget, Deficit, and Debt
- State and Local Government • Intergovernmental Relations
- Miscellaneous Issues
Core questions
- When and how should government intervene in markets?
- How should public goods be provided and financed?
- How should taxes be designed for efficiency and equity?
- How do government policies affect behaviour and welfare?
- How should responsibilities be divided across levels of government?
Key concepts
- Public goods
- Externalities and Pigouvian taxes
- Optimal taxation
- Equity-efficiency trade-off
- Fiscal federalism
- Social insurance
- Tax incidence
- Public choice
Key theories
- Welfare economics and externalities
- Pigou's analysis of external costs and corrective ('Pigouvian') taxation established the economic case for intervention to align private and social costs.
- The theory of public goods
- Samuelson characterized pure public goods (non-rival, non-excludable) and the conditions for their efficient provision.
- Fiscal federalism
- Tiebout argued that mobility among local jurisdictions ('voting with your feet') can reveal preferences for local public goods.
- Optimal taxation
- Musgrave systematized the theory of public finance and its core functions, and Mirrlees formalized optimal income taxation under asymmetric information, characterizing the equity-efficiency trade-off.
History
Public economics grew from welfare economics (Pigou, 1920) and the theory of public finance (Musgrave). Samuelson's public-goods theory (1954) and Tiebout's local-expenditure model (1956) were foundational; Mirrlees's optimal-tax theory (1971) and the public-choice school reshaped it. Modern public economics is strongly empirical, evaluating tax and transfer policies with quasi-experimental methods.
Debates
- Efficiency versus equity in taxation
- Optimal-tax theory makes explicit the trade-off between redistribution and the efficiency costs of taxation, a central and contested policy question.
- How big should government be?
- Debate persists over the proper scope of public provision, weighing market failures against government failures.
Key figures
- Arthur Pigou
- Paul Samuelson
- Charles Tiebout
- Richard Musgrave
- James Mirrlees
Related topics
Seminal works
- pigou-1920
- samuelson-1954
- tiebout-1956
- mirrlees-1971
Frequently asked questions
- What is a public good?
- A good that is non-rival (one person's use doesn't reduce another's) and non-excludable (people can't easily be prevented from using it), such as national defence — typically underprovided by markets.
- What is a Pigouvian tax?
- A tax set equal to the external cost of an activity (e.g., a carbon tax) so that private decision-makers internalize the social cost.