ECX5953 Economics
Money and Prices in the Long Run
This chapter is the money-and-inflation core of ECX5953 Economics at Monash University — the long-run macro block that moves from real quantities to the price level itself. You will learn what money is and the three jobs it does (medium of exchange, unit of account, store of value), how fractional-reserve banking creates money with a money multiplier of 1/R, how the Reserve Bank of Australia steers the economy through the cash rate and open-market operations toward a 2–3% inflation target, and why the quantity theory MV = PY makes money growth the driver of inflation. It closes with the Fisher effect (i = r + π) and the real costs of inflation.
What this chapter covers
- 01The three functions of money: medium of exchange, unit of account, store of value
- 02Commodity money vs fiat money, and money as the most liquid asset
- 03Fractional-reserve banking: the reserve ratio R and how banks create money by lending
- 04The money multiplier = 1/R and the maximum money the banking system can create
- 05The Reserve Bank of Australia: the cash rate, open-market operations, and the 2–3% inflation target
- 06The quantity theory of money MV = PY and its growth-rate form %ΔM + %ΔV = %ΔP + %ΔY
- 07The classical dichotomy and monetary neutrality: money moves nominal, not real, variables in the long run
- 08The value of money 1/P: a monetary injection lowers 1/P and raises the price level P
- 09The Fisher effect i = r + π: inflation adds to the nominal rate one-for-one, leaving the real rate unchanged
- 10The costs of inflation: shoe-leather, menu costs, relative-price variability, the inflation-induced tax distortion, confusion, and unanticipated redistribution from creditors to debtors
Worked example: the money multiplier and money creation
- +1Money multiplier. The money multiplier = 1 ⁄ R = 1 ⁄ 0.125 = 8 (put the reserve ratio in as a decimal).
- +1Maximum money. total money = initial deposit × multiplier = $6,000 × 8 = $48,000.
- +1New money created. The original $6,000 was already money, so the banking system creates $48,000 − $6,000 = $42,000 of new money through lending.
- +1Higher reserve ratio. With R = 20%, multiplier = 1 ⁄ 0.20 = 5, so maximum money = $6,000 × 5 = $30,000. A higher reserve ratio means banks lend a smaller share of each deposit, so the multiplier and money created both fall.
Key terms
- Money
- The set of assets people regularly use to buy goods and services, defined by three functions: a medium of exchange, a unit of account and a store of value. Money is the most liquid asset.
- Fiat money vs commodity money
- Fiat money has value only by government decree and common acceptance (modern banknotes); commodity money has intrinsic value of its own (such as gold). Australia uses fiat money.
- Reserve ratio (R)
- The fraction of deposits a bank holds as reserves rather than lending out. Under fractional-reserve banking R is well below 100%, which is what lets the banking system create money.
- Money multiplier
- The amount of money the banking system creates from each dollar of reserves, equal to 1/R. With R = 10% the multiplier is 10; with R = 12.5% it is 8. It is a maximum, assuming banks lend all excess reserves and the public redeposits everything.
- Cash rate
- The interest rate on overnight loans between banks, which the Reserve Bank of Australia targets as its main monetary-policy instrument, using open-market operations (buying or selling government securities) and aiming to keep inflation within a 2–3% band.
- Quantity theory of money
- MV = PY (M = money, V = velocity, P = price level, Y = real output). With velocity stable and money neutral, a rise in money growth above output growth causes proportionate inflation: %ΔP ≈ %ΔM − %ΔY.
- Monetary neutrality (classical dichotomy)
- The proposition that in the long run a change in the money supply affects only nominal variables (the price level, nominal wages) and not real variables (output, real wages, relative prices).
- Fisher effect
- The nominal interest rate equals the real interest rate plus the inflation rate: i = r + π. A rise in expected inflation raises the nominal rate roughly one-for-one, leaving the real rate unchanged in the long run.
Money and Prices in the Long Run FAQ
Why does printing money cause inflation in the long run?
Because of the quantity theory MV = PY. Velocity V is roughly stable and, in the long run, money is neutral — extra money does not raise real output Y. So a rise in the money supply M shows up mostly in the price level P. In growth-rate form, inflation ≈ money growth − output growth, which is why money growth persistently above output growth drives inflation (and, in the extreme, hyperinflation). More money lowers the value of money 1/P and raises P; it does not raise it the other way round.
Does inflation change the real interest rate?
No, not in the long run. The Fisher effect says i = r + π: a rise in expected inflation raises the nominal rate one-for-one, leaving the real rate r (set by saving and investment) unchanged. The catch is tax: because tax is charged on the nominal return, higher inflation quietly lowers the after-tax real return on saving — the inflation-induced tax distortion, one of the listed costs of inflation.
Can AI help me with money and prices in the long run in ECX5953?
Yes, as a study aid. Sia can explain the concepts step by step — the three functions of money, how the money multiplier 1/R creates money, how the RBA uses the cash rate, why MV = PY makes money growth drive inflation, and how the Fisher effect i = r + π works — and can walk you through practice questions of your own. It is a learning tool to build understanding, not a source of exam or assignment answers and not a guarantee of any grade; always follow Monash's assessment rules (generative AI is not permitted in the Mid-Semester Test) and confirm requirements on Moodle.
Exam move
Anchor this chapter on three habits. First, learn the money mechanics in words: the three functions of money, fractional-reserve banking, and the money multiplier 1/R — then drill one clean calculation (deposit × 1/R for the maximum money, remembering a higher reserve ratio creates less money). Second, get the quantity-theory direction automatic: MV = PY with V stable and money neutral means inflation ≈ money growth − output growth, and a monetary injection lowers the value of money 1/P while raising the price level P — never the reverse. Third, keep real and nominal apart using the Fisher effect i = r + π: inflation adds to the nominal rate one-for-one, leaves the real rate unchanged, and the tax distortion bites because tax falls on the nominal return. Rehearse stating the formula, the arithmetic and the direction in that order, and be able to name the costs of inflation. Because the final exam's duration and open- or closed-book status are not stated in the unit materials, budget your time in proportion to the marks on each question and confirm the exam length and rules on Moodle.
Working through Money and Prices in the Long Run in ECX5953? Sia is AskSia’s AI Economics tutor — ask any ECX5953 Money and Prices in the Long Run question and get a clear, step-by-step explanation grounded in how ECX5953 is taught and assessed. Read this chapter free, then take your hardest questions to Sia.
