Aggregate Demand, Aggregate Supply, and Monetary Policy: Study Guide (Ch. 9–11)

Aggregate Demand and Aggregate Supply

Aggregate Demand (AD)

The aggregate demand curve shows the total quantity of goods and services demanded across all levels of an economy at various price levels.

• Formula: $AD = C + I + G + NX$

• C: Consumption

• I: Investment

• G: Government spending

• NX: Net exports (exports minus imports)

Why AD is Downward Sloping

• Wealth Effect: Higher price levels reduce the real value of household wealth, leading to lower consumption.

• Interest Rate Effect: Higher prices increase the demand for money, raising interest rates and reducing investment.

• Trade Effect: Higher domestic prices make exports less competitive and imports more attractive, reducing net exports.

Shifts in Aggregate Demand

• Interest Rates: Lower interest rates increase AD; higher rates decrease AD.

• Taxes: Lower taxes increase AD; higher taxes decrease AD.

• Government Spending: Increased government spending shifts AD right.

• Expectations: Optimism about the future increases AD.

• Exchange Rates: A stronger domestic currency decreases AD by reducing net exports.

Aggregate Supply (AS)

Aggregate supply represents the total quantity of goods and services that firms are willing and able to produce at different price levels.

Short-Run Aggregate Supply (SRAS)

• SRAS is upward sloping due to:

  • Sticky Wages: Wages adjust slowly, so higher prices increase profits and output.

  • Menu Costs: Firms are slow to change prices, causing output to rise when prices increase.

  • Misperceptions: Firms may misinterpret price level changes as changes in relative prices.

Shifts in SRAS

• Labour or Capital Increases: Shift SRAS right.

• Technological Improvements: Shift SRAS right.

• Increase in Input Costs: Shift SRAS left.

• Expected Inflation: Shift SRAS left.

Long-Run Aggregate Supply (LRAS)

• LRAS is vertical at the economy's potential GDP.

• Determined by:

  • Labour

  • Capital

  • Technology

Equilibrium

• Short Run: Where AD and SRAS intersect.

• Long Run: Where AD, SRAS, and LRAS all meet.

Macroeconomic Fluctuations

• Recession: AD shifts left, leading to lower GDP and price level.

• Inflationary Gap: AD shifts right beyond LRAS, causing higher prices.

Money and Banking

Definition and Functions of Money

Money is any asset that is widely accepted as payment for goods and services or for the repayment of debt.

• Medium of Exchange: Facilitates transactions.

• Unit of Account: Provides a common measure for valuing goods and services.

• Store of Value: Retains value over time.

• Standard of Deferred Payment: Used to settle debts payable in the future.

Types of Money

• Commodity Money: Has intrinsic value (e.g., gold, silver).

• Fiat Money: Value by government decree; no intrinsic value (e.g., paper currency).

Money Supply in Canada

• M1+: Currency plus chequable deposits.

• M1++: Includes M1+ and savings accounts.

Banking System and Money Creation

• Banks accept deposits and make loans, operating under a fractional reserve system (only a fraction of deposits are kept as reserves).

• Money Multiplier: Indicates how much the money supply increases with each dollar of reserves.

Formula:

$Money\ Multiplier = \frac{1}{Reserve\ Ratio}$

• Example: If reserve ratio is 10%, multiplier is 10.

• Limitations: Banks may hold excess reserves; people may hold cash, reducing the multiplier effect.

Monetary Policy

Definition and Goals

Monetary policy refers to actions by the Bank of Canada to manage the money supply and interest rates to achieve macroeconomic objectives.

• Goals:

  • Price stability (control inflation)

  • High employment

  • Financial stability

  • Economic growth

Tools of Monetary Policy

• Open Market Operations: Buying government bonds increases the money supply; selling bonds decreases it.

• Interest Rates: Lowering rates encourages borrowing and spending; raising rates discourages it.

Types of Monetary Policy

• Expansionary Policy: Used during recessions; lowers interest rates to increase AD and GDP.

• Contractionary Policy: Used to combat inflation; raises interest rates to decrease AD and inflation.

Money Demand

• Downward sloping: Higher interest rates reduce the quantity of money demanded.

Important Concepts

• Liquidity Trap: When interest rates are near zero, monetary policy becomes less effective.

• Time Lags: There is a delay between policy implementation and its effects on the economy.

Key Formulas and Graph Rules

• Aggregate Demand: $AD = C + I + G + NX$

• Money Multiplier: $Money\ Multiplier = \frac{1}{Reserve\ Ratio}$

Graphical Representations

• AD: Downward sloping

• SRAS: Upward sloping

• LRAS: Vertical

Shift Triggers

Curve	Shift Factors
AD	Interest rates, Taxes, Government spending, Expectations, Exchange rates
SRAS	Wages/input costs, Technology, Expectations
LRAS	Labour, Capital, Technology

Exam Tips and Common Questions

• Always identify the direction of the shift (left or right).

• State the effect on both GDP and the price level.

• Mention whether the effect is in the short run or long run.

• Use proper terminology (AD, SRAS, LRAS).

Common Questions and Answers

Question	Answer
What happens when interest rates rise?	AD shifts left (decreases)
What happens during expansionary policy?	AD shifts right (increases)
Difference between movement vs shift?	Movement: caused by price change; Shift: caused by external factor change

Additional info: For a deeper understanding, students should practice drawing AD-AS diagrams and analyzing the effects of various shocks and policy responses on equilibrium output and price level.