Gross Domestic Product (GDP)

Expenditures Approach to Calculating GDP

The expenditures approach sums all spending on final goods and services produced within a country during a specific period. This method is widely used to measure a nation's economic output.

• Formula: Where:

  • C = Consumption

  • I = Investment

  • G = Government Spending

  • X = Exports

  • M = Imports

• Value-Added Approach: Calculates the additional value created at each stage of production. The sum of value added at all stages equals the final market value of the good.

• Disposable Income: Income available to households after taxes.

• Savings: The portion of disposable income not spent on consumption.

• Example: If a car manufacturer buys steel for $5,000, makes a car sold for $20,000, the value added is $15,000.

Limitations of GDP as an Indicator of Economic Well-Being

• Excludes non-market transactions (e.g., household labor, volunteer work).

• Does not account for the underground economy.

• Ignores environmental degradation and resource depletion.

• Does not measure income distribution or leisure time.

• Example: GDP may rise due to increased pollution, but well-being may not improve.

Nominal vs. Real GDP

• Nominal GDP: Measures output using current prices, not adjusted for inflation.

• Real GDP: Measures output using constant prices, adjusted for inflation.

• GDP Deflator: A price index measuring the average price of all goods and services.

• Example: If nominal GDP is $1,100 and the GDP deflator is 110, real GDP is $1,000.

Inflation and Price Indices

Consumer Price Index (CPI) and Rate of Inflation

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

• Calculating CPI:

• Rate of Inflation:

• Example: If CPI rises from 200 to 210, inflation rate is 5%.

Limitations of the CPI

• Substitution bias: Consumers may switch to cheaper goods, but CPI assumes a fixed basket.

• Quality changes: Improvements in product quality may not be fully reflected.

• New products: Delay in including new goods can overstate inflation.

• Does not reflect individual consumption patterns.

Inflation, Deflation, and Disinflation

• Inflation: Sustained increase in the general price level.

• Deflation: Sustained decrease in the general price level.

• Disinflation: A reduction in the rate of inflation (prices rise more slowly).

Demand-Pull and Cost-Push Inflation

• Demand-Pull Inflation: Caused by increases in aggregate demand.

• Cost-Push Inflation: Caused by increases in production costs (e.g., wages, raw materials).

• Graphical Illustration: Demand-pull shifts the aggregate demand curve right; cost-push shifts the aggregate supply curve left.

Measuring Purchasing Power and Effects of Unanticipated Inflation

• Purchasing Power: The quantity of goods/services that can be bought with a unit of currency.

• Unanticipated Inflation: Hurts lenders and those on fixed incomes; benefits borrowers.

• Winners: Borrowers, flexible-income earners. Losers: Lenders, fixed-income recipients.

Business Cycles and Unemployment

The Four Phases of the Business Cycle

• Expansion: Rising GDP, falling unemployment.

• Peak: Highest point before a downturn.

• Contraction (Recession): Falling GDP, rising unemployment.

• Trough: Lowest point before recovery begins.

• Graphing: Business cycles are typically shown as wavy lines representing GDP over time.

• NBER Data: The National Bureau of Economic Research (NBER) officially dates US business cycles.

Measuring Unemployment

• Employed: People currently working.

• Unemployed: People not working but actively seeking work.

• Labour Force: Employed + Unemployed.

• Labour Force Participation Rate:

• Unemployment Rate:

• Example: If 150 million are employed, 10 million unemployed, labour force is 160 million, unemployment rate is 6.25%.

Sources of Unemployment

• Frictional: Short-term, between jobs.

• Structural: Mismatch between skills and jobs.

• Cyclical: Due to economic downturns.

• Seasonal: Due to seasonal work patterns.

• Full Employment: When only frictional and structural unemployment exist (no cyclical unemployment).

• Natural Rate of Unemployment: The sum of frictional and structural unemployment.

Limitations of Official Unemployment Figures

• Discouraged workers not counted as unemployed.

• Part-time workers seeking full-time work are considered employed.

• Does not measure underemployment or job quality.

Consumption, Saving, and Investment

The Consumption Function

• Shows the relationship between consumption and disposable income. Where:

  • C = Consumption

  • a = Autonomous consumption

  • b = Marginal propensity to consume (MPC)

  • Y_d = Disposable income

• MPC (Marginal Propensity to Consume): The fraction of additional income spent on consumption.

• MPS (Marginal Propensity to Save): The fraction of additional income saved.

Non-Income Determinants of Consumption

• Wealth

• Expectations about future income/prices

• Interest rates

• Household debt

• Taxes

• Effect: Changes in these factors shift the consumption function up or down.

Determinants of Investment Spending

• Interest rates (inverse relationship)

• Expected returns/profits

• Business taxes

• Technological change

• Capacity utilization

Income-Expenditure Model and Equilibrium GDP

Solving for Equilibrium Real GDP

• Equilibrium occurs where aggregate expenditure equals output (Y).

• Simple Model:

• Graphing: The equilibrium is where the 45-degree line (Y = AE) intersects the aggregate expenditure line.

The Simple Spending Multiplier

• Measures the change in equilibrium GDP resulting from a change in autonomous spending.

• Formula:

• Example: If MPC = 0.8, multiplier = 5. A $100 increase in spending increases GDP by $500.

Summary Table: Key Macroeconomic Indicators

Additional info: Academic context and formulas have been expanded for clarity and completeness. Examples and applications are provided for each major concept to aid understanding.