Money, Banking, and Inflation: Key Concepts in Macroeconomics

A Brief History of Money: From Barter to Commodity to Fiat

Barter System

The barter system involves the direct exchange of goods or services without the use of money.

• Double coincidence of wants: Both parties must want what the other offers, making transactions time-consuming and inefficient.

• Example: A farmer wants shoes and must find a shoemaker who wants wheat.

Commodity Money

Commodity money uses goods with intrinsic value (such as gold) as a medium of exchange.

• Intrinsic value: The commodity itself has value outside its use as money.

• Difficulty: Controlling the supply and portability of commodity money can be challenging.

• Example: Gold coins used in trade.

Fiat Money

Fiat money is currency authorized by a central bank, not backed by a physical commodity.

• Expectation: Households and firms trust the value of fiat money due to government backing.

• Example: Modern paper currency such as the US dollar.

The Functions of Money

Medium of Exchange

Money facilitates transactions by being accepted as payment for goods and services.

• Legal tender: Buyers and sellers accept money for trade.

Unit of Account

Money provides a standard measure for valuing goods and services.

• Advantage: Efficiency in pricing and comparison.

• Example: Prices listed in dollars at a store.

Store of Value

Money allows individuals to save purchasing power for future use.

• Example: Saving cash for future expenses.

Standard of Deferred Payment

Money enables borrowing and lending by serving as a means to settle debts in the future.

• Disadvantage: Inflation can erode purchasing power over time.

• Advantage: Liquidity makes it easy to convert into other forms of payment.

Money Supply and Banking

Definition of Money

Money is a stock, representing the value of currency in circulation and deposits held in banks.

Bank Money Creation

Banks create money by loaning out reserves in excess of required reserves.

• Required reserves: The legally mandated minimum reserves a bank must hold, based on its deposits.

The Simple Deposit Multiplier

The deposit multiplier shows how much the money supply can increase based on new deposits.

• Formula:

$\text{Simple Deposit Multiplier} = \frac{1}{RR}$

• Total change in checking account deposits: $\text{Change in bank reserves} \times \frac{1}{RR}$

• Overall change in money supply: Increase in deposits minus decline in currency.

• Real-world multiplier: Usually lower than the simple deposit multiplier due to currency leakage and other factors.

Inflation and the Quantity Theory of Money

Long-Run Implications

The quantity theory of money explains the relationship between money supply growth and inflation.

• Formula:

$\%\text{ Change in } M + \%\text{ Change in } V = \%\text{ Change in } P + \%\text{ Change in } Y$

• Velocity of money (V): The average number of times each dollar is used in a purchase.

• If velocity is constant in the long run:

$\text{Inflation rate} = \text{Growth rate of money} - \text{Growth rate of real GDP}$

• Implication: Inflation occurs when money supply grows faster than real GDP.

Short-Run Implications: The Phillips Curve

The Phillips curve illustrates the short-run trade-off between inflation and unemployment.

• Ceteris paribus: The short-run Phillips curve shows a negative relationship between inflation and unemployment.

• Policy movements:

  • Expansionary policies: Lower unemployment, higher inflation (curve shifts leftward).

  • Contractionary policies: Lower inflation, higher unemployment (curve shifts rightward).