Markets: Demand, Supply, and Equilibrium

Basic Mechanisms of a Market

Markets are systems where buyers and sellers interact to determine the prices and quantities of goods and services. The fundamental forces in a market are demand and supply.

• Demand: The quantity of a good or service that consumers are willing and able to purchase at various prices.

• Supply: The quantity of a good or service that producers are willing and able to offer for sale at various prices.

• Market Equilibrium: The point where the quantity demanded equals the quantity supplied, determining the equilibrium price and quantity.

Movements vs. Shifts in Demand and Supply

It is important to distinguish between a movement along a curve and a shift of the curve itself.

• Movement: Caused by a change in the current price of the product, resulting in a movement along the demand or supply curve.

• Shift: Caused by factors other than the product's price (e.g., income, tastes, number of buyers, technology), resulting in the entire curve shifting left or right.

Table: Summary of Shifts in Demand and Supply

Additional info: Table entries inferred from standard macroeconomics content.

Surplus, Shortage, and Market Adjustment

• Surplus: Occurs when quantity supplied exceeds quantity demanded at a given price. This puts downward pressure on price.

• Shortage: Occurs when quantity demanded exceeds quantity supplied at a given price. This puts upward pressure on price.

• Market Adjustment: Prices adjust to eliminate surpluses and shortages, moving the market toward equilibrium.

Example: If the price is set above equilibrium, a surplus results, leading sellers to lower prices. If the price is below equilibrium, a shortage results, leading buyers to bid up prices.

Effects of Shifts on Equilibrium

• Shifts in demand or supply change the equilibrium price and quantity.

• Increase in demand: Raises both equilibrium price and quantity.

• Increase in supply: Lowers equilibrium price but increases equilibrium quantity.

Measuring Economic Activity: GDP

Methods of Calculating GDP

Gross Domestic Product (GDP) measures the total value of all final goods and services produced within a country in a given period.

• Value-Added Method: Sum of value added at each stage of production.

• Total Expenditure Method: Sum of all expenditures on final goods and services: , where C = consumption, I = investment, G = government spending, X = exports, M = imports.

• Total Income Method: Sum of all incomes earned by factors of production (wages, rent, interest, profit).

Shortcomings of GDP

• Does not account for non-market transactions (e.g., household labor).

• Ignores environmental degradation and resource depletion.

• Does not measure income distribution or well-being.

• May be biased by the informal economy or unreported activities.

Real vs. Nominal GDP

• Nominal GDP: Measured using current prices; does not account for inflation.

• Real GDP: Measured using constant base-year prices; allows comparison across years by removing the effects of price changes.

• GDP Deflator: Measures the overall price level:

Example: If nominal GDP is \frac{10}{4} \times 100 = 250$.

Measuring Price Level: CPI and Inflation

Consumer Price Index (CPI)

• CPI measures the average change in prices paid by consumers for a fixed basket of goods and services.

• Calculated by keeping quantities constant at the base year and comparing the cost of the basket in different years.

• Formula:

Calculating Inflation Rate

• Inflation rate is the percentage change in the price level from one year to the next.

• Formula:

Example: If CPI in 2000 is 120 and in 2001 is 150, then .

Nominal vs. Real Values

• Nominal values: Measured in current dollars, not adjusted for inflation.

• Real values: Adjusted for inflation, reflect purchasing power.

• To convert nominal to real:

Unemployment and Labor Market

Types of Unemployment

• Frictional Unemployment: Short-term, occurs when people are between jobs or entering the labor force.

• Structural Unemployment: Caused by changes in the structure of the economy, such as technological change or shifts in demand.

• Cyclical Unemployment: Caused by economic downturns or recessions.

Example: A worker laid off due to automation faces structural unemployment; a new graduate searching for a job faces frictional unemployment.

Calculating Unemployment and Labor Force Participation Rates

• Unemployment Rate:

• Labor Force Participation Rate:

Example: If 95 million are employed, 5 million unemployed, and working-age population is 125 million: Labor force = 100 million, so participation rate = .

Causes of Unemployment Above Equilibrium

• Unemployment can persist if the actual wage is above the equilibrium wage due to:

  • Minimum wage laws

  • Labor unions

  • Efficiency wages (firms pay above equilibrium to increase productivity)

Business Cycles and Economic Growth

Phases of the Business Cycle

• Expansion: Period of increasing economic activity and growth.

• Peak: The highest point before a downturn.

• Recession: Period of declining economic activity.

• Trough: The lowest point before recovery begins.

Stylized Facts of Recession: Rising unemployment, falling output, reduced consumer spending.

Calculating Growth Rates and the Rule of 70

• Growth Rate:

• Rule of 70: Estimates the number of years for a variable to double at a constant growth rate:

Application: Practice Questions and Data Interpretation

Sample Multiple Choice and Calculation Questions

• Identify shifts in demand or supply based on changes in tastes, population, technology, or prices of related goods.

• Interpret graphs to determine surplus or shortage at given prices.

• Calculate GDP using value-added and expenditure approaches.

• Compute CPI, inflation rates, and adjust nominal values to real values using price indices.

• Apply labor market formulas to find unemployment and participation rates.

Example Table: Value-Added Approach

Value added at each stage is the difference between the sale price and the cost of inputs purchased from the previous stage.

Example Table: CPI Calculation

Cost of basket in 2012: Cost of basket in 2023:

Additional info: Calculations and explanations expanded for clarity and completeness.