Market failure and sustainable policy
Market Failure and Government Intervention
Welfare analysis distinguishes private incentives from social costs and benefits under a stated model. Policy evaluation must also consider information, implementation, distribution and government failure; no particular country’s current legislation or health scheme is assumed.
Categories of market failure
- Public goods are non-rival and non-excludable, so the free-rider problem causes underprovision: national defence, street lighting, flood defences, lighthouse services.
- In common policy models, merit goods are judged underconsumed and demerit goods overconsumed relative to a stated social benchmark; information failures can contribute, as with screening programmes and tobacco.
- Externalities: negative production (emissions, aircraft noise near Larnaca), negative consumption (smoking), positive production (training, research), positive consumption (vaccination).
- Also market power, inequality, factor immobility and macroeconomic instability.
Welfare analysis
- The social optimum is where MSB = MSC; the free market produces where MPB = MPC.
- Negative externality: MSC lies above MPC, so output is excessive and there is a deadweight loss triangle. A Pigouvian tax equal to marginal external cost at the optimum corrects it; tradable permits fix the quantity instead.
- Positive externality: MSB exceeds MPB, output is too low, and a subsidy equal to marginal external benefit is the textbook remedy.
Instruments and government failure
- Taxes, subsidies, regulation and standards, tradable permits, public provision, information campaigns, price controls, cost-benefit analysis.
- Government failure: imperfect information, administrative and compliance costs, unintended consequences, regulatory capture, rent-seeking and time inconsistency.
Worked example
Marginal private cost is MPC = 20 + 2 Q, marginal external cost is a constant €10 and demand is MPB = MSB = 90 − 2 Q. The free market sets 90 − 2 Q = 20 + 2 Q, giving Q = 17.5 and P = €55. The social optimum sets 90 − 2 Q = 30 + 2 Q, giving Q = 15 and P = €60. A Pigouvian tax of €10 per unit aligns private with social cost, raises €150 of revenue at the optimum, and removes a deadweight loss of ½ × 2.5 × €10 = €12.50.
Traps that cost marks
- Calling anything state-provided a public good; the test is non-rivalry and non-excludability.
- Drawing MSC below MPC for a negative externality.
- Setting the corrective tax equal to total external cost rather than marginal external cost at the optimum.
- Assuming intervention is automatically efficient; marks are available for evaluating government failure.