The Role of Government in Microeconomics
Governments intervene in markets to correct market failures, redistribute income, and achieve social objectives. Key tools include price controls (ceilings and floors), indirect taxes, and subsidies. Each intervention creates predictable effects on equilibrium price and quantity, and involves trade-offs between efficiency and equity. Understanding the welfare effects on consumers, producers, and the government is essential for IB evaluation.
Key Terms & Definitions
Price Ceiling (Maximum Price)
A legally imposed maximum price set below the equilibrium price, creating a shortage (excess demand). E.g., rent controls.
Price Floor (Minimum Price)
A legally imposed minimum price set above the equilibrium price, creating a surplus (excess supply). E.g., minimum wage.
Indirect Tax
A tax on goods/services paid by the producer but partially passed on to consumers. Shifts supply curve leftward (upward).
Specific Tax
A fixed amount of tax per unit of output (e.g., $2 per litre). Shifts supply curve upward by the tax amount.
Ad Valorem Tax
A percentage tax on the price of a good (e.g., VAT at 20%). Causes the supply curve to rotate, not shift parallel.
Subsidy
A payment from government to producers to lower costs, shifting supply rightward and reducing the market price.
Consumer Surplus
The difference between what consumers are willing to pay and what they actually pay — the area above price and below demand curve.
Producer Surplus
The difference between the price producers receive and their minimum acceptable price — the area below price and above supply curve.
Deadweight Loss
The loss of total welfare (consumer + producer surplus) resulting from market intervention or market failure.
IB Diagram
Accurate IB-style diagram — straight lines, labelled axes
IB Diagram
Price Ceiling — ShortageIB standard: straight lines · P on Y-axis · Q on X-axis · labels at end of curves · dashed drop lines to axes
Diagram Notes: Four separate diagrams: (1) Price ceiling with shortage and deadweight loss. (2) Price floor with surplus and deadweight loss. (3) Specific tax — supply shifts up by tax amount, consumer and producer share labeled. (4) Subsidy — supply shifts right, lower price, higher quantity.