Supply, Demand, and Government Policies

Introduction

This chapter explores how government interventions such as price controls and taxes affect market outcomes. Using the supply and demand model, we analyze the effects of price ceilings, price floors, and taxes, and discuss the concept of tax incidence and its relationship with elasticity.

Price Controls

Price Ceilings

A price ceiling is a legal maximum on the price at which a good can be sold. Governments may impose price ceilings when they believe the market price is too high for consumers.

• Not Binding: If set above the equilibrium price, the ceiling has no effect on the market.

• Binding Constraint: If set below the equilibrium price, the ceiling is effective, and the market price cannot rise above it. This leads to a shortage, as quantity demanded exceeds quantity supplied.

• Rationing Mechanisms: When shortages occur, sellers must ration goods, often leading to long lines, favoritism, and inefficiency.

Example: If the equilibrium price of muffins is $3, a price ceiling at $5 is not binding, but a ceiling at $2 is binding, causing a shortage.

Rent Control

• Rent control is a common example of a price ceiling, intended to make housing more affordable.

• In the short run, supply and demand for apartments are inelastic, so shortages are small.

• In the long run, both supply and demand become more elastic, leading to larger shortages and reduced quality and quantity of housing.

Price Floors

A price floor is a legal minimum on the price at which a good can be sold. Governments may impose price floors to ensure sellers receive a minimum income.

• Not Binding: If set below the equilibrium price, the floor has no effect.

• Binding Constraint: If set above the equilibrium price, the floor is effective, and the market price cannot fall below it. This leads to a surplus, as quantity supplied exceeds quantity demanded.

• Rationing Mechanisms: Surpluses may result in sellers competing for buyers, sometimes leading to inefficiency or waste.

Example: If the equilibrium price of muffins is $3, a price floor at $1 is not binding, but a floor at $4 is binding, causing a surplus.

Minimum Wage

• The minimum wage is a price floor in the labor market.

• If set above the equilibrium wage, it causes unemployment: the quantity of labor supplied exceeds the quantity demanded.

• Some workers benefit from higher wages, but others may lose their jobs.

Evaluating Price Controls

• Markets typically allocate resources efficiently through prices.

• Price controls can obscure price signals, leading to inefficiency and unintended consequences.

• Alternative policies, such as rent or wage subsidies, may achieve goals with fewer side effects.

Taxes and Tax Incidence

Introduction to Taxes

Governments levy taxes to raise revenue for public projects. Taxes can be imposed on buyers or sellers, affecting market outcomes and the division of the tax burden, known as tax incidence.

How Taxes Affect Market Outcomes

• Taxes discourage market activity, reducing the equilibrium quantity sold.

• Both buyers and sellers share the burden of the tax, regardless of whom the tax is legally imposed on.

• Taxes create a wedge between the price buyers pay and the price sellers receive.

Tax on Sellers

• The supply curve shifts upward by the amount of the tax.

• Buyers pay a higher price; sellers receive a lower price (after tax).

• Quantity sold decreases.

Tax on Buyers

• The demand curve shifts downward by the amount of the tax.

• Buyers pay a higher effective price (including tax); sellers receive a lower price.

• Quantity sold decreases.

Equivalence of Taxes on Buyers and Sellers

• Whether a tax is levied on buyers or sellers, the outcome is the same: the tax drives a wedge between the price buyers pay and the price sellers receive, and both share the burden.

Tax Incidence and Elasticity

• The division of the tax burden depends on the relative elasticities of supply and demand.

• Elasticity measures the responsiveness of quantity supplied or demanded to changes in price.

• The side of the market (buyers or sellers) that is less elastic (less responsive to price changes) bears more of the tax burden.

Formulas

• Tax Wedge: The difference between the price buyers pay () and the price sellers receive () equals the tax ():

• Elasticity of Demand:

• Elasticity of Supply:

Conclusion

Price controls and taxes are common government interventions in markets. Their effects can be analyzed using supply and demand models. The burden of a tax depends on the relative elasticities of supply and demand, not on whom the tax is legally imposed. Understanding these concepts is essential for evaluating the impact of government policies on economic welfare.