Chapter 4.3 – Price Ceilings and Price Floors

Definitions and Key Concepts

Price controls are government-imposed limits on the prices that can be charged for goods and services. They are used to address perceived unfairness or to stabilize markets, but often have unintended consequences.

• Price ceiling: Legally determined maximum price for a good or service (e.g., rent control, price gouging laws).

• Price floor: Legally determined minimum price for a good or service (e.g., minimum wage, agricultural price supports).

• Binding price control: A control that prevents the market from reaching equilibrium. A ceiling is binding if set below equilibrium price; a floor is binding if set above equilibrium price.

• Shortage: Occurs when quantity demanded exceeds quantity supplied at the controlled price. Created by a binding price ceiling.

• Surplus: Occurs when quantity supplied exceeds quantity demanded at the controlled price. Created by a binding price floor; in labor markets, this is unemployment.

• Illegal (black) market: Transactions at prices violating the regulation (e.g., apartments rented above legal rent).

• Deadweight loss: Reduction in economic surplus due to fewer units traded than at equilibrium.

Key Points

• Binding price controls limit the quantity traded to the smaller of quantity demanded or supplied.

• Price ceilings (e.g., rent control) cause shortages, benefit some renters, harm landlords and unsuccessful renters, and lead to non-price rationing (waiting lists, discrimination).

• Price floors (e.g., minimum wage) cause surpluses, benefit employed workers, harm employers and unemployed workers.

• Transfers between buyers and sellers are not a societal loss; deadweight loss arises from units not traded.

• Efficiency is a positive (descriptive) statement; desirability is a normative (prescriptive) question.

• Minimum wage debates focus on income gains vs. job losses; empirical studies (e.g., Card and Krueger) show mixed effects.

• Price gouging laws prevent windfall gains but create shortages and discourage supply increases.

Examples

• Rent control in New York City: shortage of apartments, emergence of black markets.

• Minimum wage laws: unemployment among low-skilled workers.

Additional info: Price controls are often implemented during emergencies or to protect vulnerable groups, but economists generally agree they reduce market efficiency.

Chapter 4.4 – The Economic Effect of Taxes

Definitions and Key Concepts

Taxes on goods and services affect market prices, quantities, and the distribution of economic surplus. Understanding tax incidence is crucial for policy analysis.

• Per-unit (excise) tax: Fixed dollar amount per unit sold (e.g., gasoline tax).

• Tax incidence: Division of tax burden between buyers and sellers.

• Buyers’ burden: Increase in price paid by buyers due to the tax.

• Sellers’ burden: Decrease in price received by sellers after paying the tax.

• Tax revenue: Tax per unit multiplied by quantity sold after tax.

• Excess burden (deadweight loss): Loss of consumer and producer surplus not offset by tax revenue.

• Efficient tax: Tax with small excess burden relative to revenue raised.

Key Points

• Tax on sellers shifts supply curve up by the tax amount; tax on buyers shifts demand curve down.

• After tax, quantity sold falls, buyers pay more, sellers receive less; price change is less than the full tax unless demand is perfectly inelastic.

• Some surplus becomes government revenue; some disappears as excess burden.

• Incidence depends on relative price sensitivity (elasticity) of demand and supply, not on legal responsibility for payment.

• Steep (inelastic) demand: buyers bear most of the tax; steep supply: sellers bear most.

• Example: FICA tax is legally split, but workers bear most due to inelastic labor supply.

Formulas

Examples

• Gasoline tax: buyers pay more, sellers receive less, government collects revenue.

• Cigarette tax: incidence falls more on buyers due to inelastic demand.

Chapter 4 Appendix – Quantitative Demand and Supply Analysis

Definitions and Key Concepts

Demand and supply equations provide a mathematical framework for analyzing market equilibrium and the effects of policies.

• Demand equation: ; quantity demanded decreases as price increases.

• Supply equation: ; quantity supplied increases as price increases.

• Equilibrium condition: ; solve for equilibrium price and quantity.

• Price intercept: Price at which quantity is zero; where curve meets price axis.

• Consumer surplus: Area below demand curve and above price.

• Producer surplus: Area above supply curve and below price.

• Economic surplus: Sum of consumer and producer surplus; maximized at equilibrium.

Key Points

• Equations allow precise calculation of equilibrium and surplus.

• Binding price controls: compare controlled price to equilibrium price; quantity traded is determined by the short side.

• Deadweight loss is the surplus lost on units not traded due to controls or taxes.

Formulas

• Set to solve for equilibrium price .

• Substitute to find equilibrium quantity .

Chapter 5.1 – Externalities and Economic Efficiency

Definitions and Key Concepts

Externalities occur when the actions of producers or consumers affect third parties. They lead to market failures and inefficiency.

• Externality: Benefit or cost affecting someone not directly involved in the transaction.

• Negative externality: Cost imposed on others (e.g., pollution).

• Positive externality: Benefit received by others (e.g., vaccination).

• Private cost/benefit: Cost/benefit to producer/consumer.

• Social cost/benefit: Total cost/benefit including externalities.

• Marginal private/social cost/benefit: Additional cost/benefit from one more unit.

• Economic efficiency: Achieved when marginal social benefit equals marginal social cost.

• Market failure: Market does not produce efficient output; externalities are a cause.

• Property rights: Rights to exclusive use of property; incomplete rights lead to externalities.

Key Points

• Negative externality: market supply reflects only private cost; social cost is higher; market overproduces.

• Positive externality: market demand reflects only private benefit; social benefit is higher; market underproduces.

• Deadweight loss is the area between social and private curves from efficient to market quantity.

• Externalities arise due to incomplete property rights.

Formulas

• Efficient quantity:

Examples

• Pollution from factories (negative externality).

• Vaccination (positive externality).

Chapter 5.2 – Private Solutions to Externalities: The Coase Theorem

Definitions and Key Concepts

The Coase theorem suggests that private bargaining can solve externality problems if property rights are well-defined and transaction costs are low.

• Coase theorem: Efficient outcome through private bargaining regardless of property right assignment.

• Transactions costs: Costs incurred in negotiating and enforcing agreements.

• Internalizing an externality: Making the party creating the externality bear its full cost or benefit.

• Efficient pollution reduction: Marginal benefit equals marginal cost.

Key Points

• Efficient pollution reduction is not zero; balance marginal benefit and cost.

• Assignment of property rights affects who pays, not the outcome.

• Coase theorem requires enforceable property rights, low transaction costs, and knowledge of costs/benefits.

• Private solutions fail when transaction costs are high (e.g., many affected parties).

Examples

• Neighbors negotiating over noise or pollution.

• Large-scale pollution (acid rain) requires government intervention.

Chapter 5.3 – Government Policies to Deal with Externalities

Definitions and Key Concepts

Governments use various policies to correct externalities and restore efficiency, including taxes, subsidies, regulation, and market-based approaches.

• Pigovian tax: Tax equal to marginal external cost; reduces negative externality.

• Pigovian subsidy: Subsidy equal to marginal external benefit; increases positive externality.

• Command-and-control: Direct regulation of pollution or required technology.

• Market-based approach: Uses prices and incentives (e.g., Pigovian taxes, tradable allowances).

• Tradable emissions allowances (cap-and-trade): Government sets cap, firms trade allowances.

Key Points

• Pigovian tax shifts supply to reflect social cost, reducing quantity to efficient level and internalizing externality.

• Pigovian subsidy shifts demand to reflect social benefit, increasing quantity to efficient level.

• Command-and-control is inefficient if firms have different abatement costs.

• Cap-and-trade achieves reduction at lowest cost; firms trade allowances based on abatement costs.

Examples

• Carbon tax (Pigovian tax).

• 1990 sulfur dioxide cap-and-trade program.

Chapter 5.4 – Four Categories of Goods

Definitions and Key Concepts

Goods are classified based on rivalry and excludability, affecting how markets supply them and the potential for market failure.

• Rivalry: One person's consumption prevents others from consuming the same unit.

• Excludability: Non-payers can be prevented from consuming the good.

• Private good: Rival and excludable (e.g., hamburger).

• Public good: Nonrival and nonexcludable (e.g., national defense).

• Quasi-public good: Excludable but nonrival (e.g., cable TV).

• Common resource: Rival but nonexcludable (e.g., fish in the ocean).

• Free riding: Benefiting without paying; occurs with public goods.

• Tragedy of the commons: Overuse of common resources due to ignored external costs.

Table: Classification of Goods

Key Points

• Private good demand: horizontal sum of individual demand curves.

• Public good demand: vertical sum of individual willingness to pay.

• Free riding prevents efficient supply of public goods; governments use cost–benefit analysis.

• Common resources are overused due to lack of exclusion; solutions include community norms, taxes, quotas, or permits.

Examples

• Public good: National defense.

• Common resource: Overfishing.

• Quasi-public good: Toll road.

• Private good: Hamburger.

Additional info: The root cause of market failures for public goods and common resources is the absence of enforceable property rights.

Exam Preparation Checklist

• Define and identify price ceilings, price floors, shortages, and surpluses.

• Explain winners and losers from price controls.

• Distinguish positive vs. normative analysis.

• Define tax incidence, tax revenue, excess burden, and efficient tax.

• Locate price intercepts, consumer surplus, and producer surplus on a graph.

• Define externality, private vs. social cost/benefit, and market failure.

• Explain overproduction (negative externality) and underproduction (positive externality).

• State and apply the Coase theorem.

• Explain efficient pollution reduction.

• Define and compare Pigovian tax, subsidy, command-and-control, and cap-and-trade.

• Classify goods by rivalry and excludability; explain free riding and tragedy of the commons.

• Explain public-good demand as a vertical sum.