Economics Notes on Money Supply and Inflation

The Money Supply-Demand Diagram

  • Value of Money: Denoted as $1/P$ where $P$ is the price level.
  • Price Level ($P$): Represents the average level of prices in the economy.
  • Quantity of Money: Affected by changes in the value of money; as value falls (or $P$ increases), the quantity of money demanded increases.

Equilibrium in Money Supply-Demand

  • The equilibrium condition occurs when the quantity of money demanded equals the quantity supplied.
    • At this point, the price level $P$ adjusts to equate money supply (MS) with money demand (MD).
    • Example: If MS increases from $1000 to $2000, the quantity of money demanded at a certain price level will also rise, leading to a new equilibrium.

Real vs. Nominal Variables

  • Nominal Variables: Measured in monetary units.
    • Examples: nominal GDP, nominal interest rate, nominal wage.
  • Real Variables: Measured in physical units.
    • Examples: real GDP, real interest rate, real wage.

Real Wage Calculation

  • Formula: W/PW/P where:
    • $W$ = nominal wage (e.g., $15/hour)
    • $P$ = price level (e.g., $5/unit of output)
  • Example Calculation of Real Wage:
    extRealWage=WP=155=3extunitsofoutputperhourext{Real Wage} = \frac{W}{P} = \frac{15}{5} = 3 ext{ units of output per hour}

Classical Dichotomy

  • Definition: The theoretical separation of nominal and real variables as proposed by classical economists such as Hume.
  • Key Insight: Changes in the money supply affect nominal variables but do not influence real variables.
    • Example: If the money supply doubles, all nominal variables also double, but real wages and relative prices remain unchanged.

Neutrality of Money

  • Monetary Neutrality: Changes in the money supply do not affect real variables such as output, employment, or labor supply.
  • Key Assertions:
    • Real wages ($W/P$) remain unchanged.
    • Total output is unaffected by changes in the money supply.

Velocity of Money

  • Definition: The rate at which money changes hands in the economy.
  • Formula: V=PimesYMV = \frac{P imes Y}{M}
    • Where:
    • $V$ = velocity
    • $P$ = price level
    • $Y$ = real GDP
    • $M$ = money supply

Quantity Equation

  • Rearranged from velocity formula:
    MimesV=PimesYM imes V = P imes Y
  • Links money supply with nominal GDP.

Quantity Theory of Money (5 Steps)

  1. Stability of $V$: Velocity is stable over time.
  2. Impact of Changes in $M$: A change in $M$ results in a proportional change in nominal GDP ($P imes Y$).
  3. Money Neutrality: Changes in $M$ do not affect real output ($Y$), which is determined by technology and resources.
  4. Price Changes: Price level $P$ changes in accordance with changes in $M$ and $P imes Y$.
  5. Inflation Connection: Rapid growth in money supply leads to rapid inflation.

The Fisher Effect

  • Definition: Describes the relationship between nominal interest rates and inflation over the long run.
  • Formula:
    extRealInterestRate=extNominalInterestRate−extInflationRateext{Real Interest Rate} = ext{Nominal Interest Rate} - ext{Inflation Rate}
  • Implication: In the long run, a rise in the money supply leads to an increase in the inflation rate, which in turn influences the nominal interest rate one-for-one.