Money in the Macroeconomy: Classical, Keynesian, and Post-Keynesian Perspectives
Money plays a pivotal role in any economy. Its presence and function are central to understanding macroeconomic phenomena such as inflation, output levels, and interest rates. Economists have developed various theories to explain the relationship between money, prices, and economic activity. We will explore the classical, Keynesian, and post-Keynesian approaches to money in the macroeconomy, examining different perspectives on the demand for and supply of money.
Classical Approach to Money
The classical economists, including figures like David Ricardo and John Stuart Mill, viewed money primarily as a medium of exchange. Their understanding of money's role in the economy was largely encapsulated in the Quantity Theory of Money. This theory posits a direct relationship between the amount of money in circulation and the general price level.
The Quantity Theory of Money (Classical Version)
The classical economists developed the Quantity Theory of Money, most famously articulated by Irving Fisher. This theory is often expressed through the Equation of Exchange:
M * V = P * T
Where:
- M is the total quantity of money in circulation.
- V is the velocity of circulation (the average number of times a unit of money is used to purchase goods and services in a given period).
- P is the general price level of goods and services.
- T is the total number of transactions of goods and services in an economy during a given period.
The classical economists made several key assumptions that simplified this equation and led to strong conclusions about the role of money:
- V (Velocity of Circulation) is relatively constant. They believed that the habits of people in spending money were stable and not significantly affected by changes in the money supply or interest rates.
- T (Total Transactions) is determined by real factors. They assumed that the economy operated at full employment, meaning that the number of transactions was limited by the economy's productive capacity (land, labor, capital). Changes in money supply did not affect real output in the long run.
Given these assumptions, the equation implies that any change in the money supply (M) must lead to a proportional change in the price level (P). For example, if the money supply doubles, the price level will also double, assuming V and T remain constant. This leads to the conclusion that money is "neutral" in the long run, meaning it only affects nominal variables (like prices and wages) and not real variables (like output and employment).
In the classical view, the demand for money was primarily for transactions. People held money to facilitate their day-to-day purchases. The amount of money they held was proportional to their income and the prices of goods they bought.
Keynesian Approach to Money
John Maynard Keynes revolutionized macroeconomic thought, and his views on money were significantly different from the classical perspective. In his seminal work, "The General Theory of Employment, Interest and Money" (1936), Keynes argued that money is not just a medium of exchange but also a store of value and, crucially, influences interest rates and aggregate demand.
The Liquidity Preference Theory
Keynes introduced the concept of "liquidity preference" to explain the demand for money. He argued that individuals and firms hold money for three main motives:
- The Transactions Motive: Similar to the classical view, people hold money to meet their regular, day-to-day spending needs. This demand is positively related to income.
- The Precautionary Motive: People hold money to cover unexpected expenses or emergencies. This demand is also influenced by income and the level of uncertainty in the economy.
- The Speculative Motive: This is the most significant departure from classical thought. Keynes argued that people hold money as an asset, like bonds or stocks. The decision to hold money versus other assets depends on the interest rate. When interest rates are high, the opportunity cost of holding money (which earns no interest) is high, so people prefer to hold interest-bearing assets. Conversely, when interest rates are low, the opportunity cost of holding money is low, and people may prefer to hold more money, anticipating that interest rates might rise in the future (causing bond prices to fall). This means the demand for money is inversely related to the interest rate.
The speculative motive implies that the demand for money is not fixed but is sensitive to interest rate changes. This has profound implications for monetary policy.
Money and Aggregate Demand
Unlike the classical view where money only affects prices, Keynes argued that changes in the money supply can affect real economic variables, particularly the interest rate and aggregate demand.
- Interest Rate Channel: An increase in the money supply (with demand unchanged) leads to lower interest rates as people try to buy more bonds.
- Investment and Consumption: Lower interest rates reduce the cost of borrowing, encouraging businesses to invest more in capital goods. Lower interest rates can also encourage consumers to spend more on durable goods.
- Aggregate Demand: Increased investment and consumption lead to a rise in aggregate demand.
- Output and Employment: In an economy with unemployed resources (as Keynes often assumed), an increase in aggregate demand leads to higher output and employment.
Therefore, Keynesians believe that monetary policy can be an effective tool for managing the economy, influencing not just prices but also real output and employment, especially in the short run.
Post-Keynesian Developments and Monetarism
Following Keynes, economists continued to refine the understanding of money's role. The post-Keynesian era saw the rise of Monetarism, a school of thought strongly associated with Milton Friedman. Monetarists re-emphasized the importance of the money supply in determining inflation and nominal income, but with a different perspective than the early classical economists.
Milton Friedman and the Modern Quantity Theory
Milton Friedman, a leading figure of Monetarism, argued for a modern version of the Quantity Theory of Money. He viewed the demand for money as a stable function of a few key variables, including permanent income (long-run average income) and the expected rate of inflation and interest rates. While he acknowledged that velocity could change, he argued it was more stable and predictable than Keynesian economists suggested.
Friedman famously stated, "Inflation is always and everywhere a monetary phenomenon." This means that sustained, high inflation can only occur if the money supply grows significantly faster than the real output of the economy.
The Monetarist perspective uses a modified equation of exchange:
M * V = P * Y
Where:
- M is the money supply.
- V is the velocity of money.
- P is the price level.
- Y is real income (or real output).
Monetarists believe that the velocity (V) is relatively stable or predictable. Therefore, changes in the money supply (M) have a direct and predictable impact on nominal income (P * Y). In the long run, they believe that changes in M primarily affect P (inflation), with minimal impact on Y (real output), aligning somewhat with the classical view of long-run neutrality but with a more sophisticated understanding of the demand for money.
Monetarists advocate for a steady, predictable growth rate of the money supply as the best way to maintain price stability and economic growth. They are generally skeptical of discretionary fiscal and monetary policies aimed at fine-tuning the economy.
Don Patinkin and the Integration of Money and Value Theory
Don Patinkin, in his book "Money, Interest, and Prices" (1956), made a significant contribution by attempting to integrate the theory of money into the general theory of value. He sought to build a general equilibrium model where the demand for and supply of money were treated within the same framework as the demand for and supply of other goods and services.
Patinkin's key contribution was to analyze the "real balance effect." He argued that changes in the money supply affect the real value of assets held by households. If the money supply increases, people feel wealthier because the nominal amount of money they hold has increased. This increased real wealth can lead to an increase in the demand for goods and services, even if interest rates don't change. This effect could help an economy move towards full employment equilibrium.
Patinkin's work helped bridge the gap between classical and Keynesian economics by showing how monetary factors could influence real variables through wealth effects, and how the classical conclusion of long-run neutrality might not hold if real balance effects are significant.
Gurley and Shaw: The Broader View of Money Supply
John Gurley and Edward Shaw challenged the conventional view of the money supply by arguing that it should be defined more broadly than just currency and demand deposits. They introduced the concept of "money surrogates" or "near-money" assets – financial assets that are close substitutes for money, such as savings accounts, time deposits, and short-term government securities.
Gurley and Shaw argued that these near-money assets, issued by financial intermediaries like banks and non-bank financial institutions, also play a significant role in influencing aggregate demand and the economy. They suggested that policies affecting these intermediaries and their liabilities could have a substantial impact, comparable to traditional monetary policy.
Their work broadened the scope of monetary economics, highlighting the importance of the entire financial system, not just the central bank and commercial banks, in the transmission of monetary policy and the determination of economic activity. This perspective contributed to the development of more sophisticated financial models.
Demand for Money: Perspectives Compared
Let's summarize the different perspectives on the demand for money:
Classical Perspective on Demand for Money
The demand for money is primarily for transactions.
It is directly proportional to income (Y) and the price level (P).
It is relatively insensitive to the interest rate.
Ld = k * P * Y (where k is a constant representing the proportion of income held as money).
Keynesian Perspective on Demand for Money
The demand for money arises from three motives: transactions, precautionary, and speculative.
Transactions and precautionary demands are positively related to income (Y).
Speculative demand is inversely related to the interest rate (r).
Ld = LT(Y) + LP(Y) + LS(r) Or, more simply: Ld = f(Y, r), where Y is positively related and r is negatively related.
The demand for money is sensitive to changes in both income and interest rates.
Post-Keynesian/Monetarist Perspective on Demand for Money
Milton Friedman viewed the demand for money as a stable function of permanent income (Yp) and a set of opportunity costs, including the interest rate (r) and the expected rate of inflation (πe).
He believed that while interest rates and inflation expectations influence the demand for money, the relationship is more stable and predictable than Keynes suggested.
Md/P = L(Yp, r, πe)
The focus is on the demand for real balances (M/P). Changes in nominal money supply have predictable effects on nominal income.
Don Patinkin's Contribution
Patinkin emphasized the real balance effect, meaning that the demand for money is influenced by the real value of money holdings. Changes in the money supply affect real wealth, which in turn affects the demand for goods and services. This adds another dimension to understanding how money influences the economy.
Supply of Money: Classical Version
The classical economists had a relatively simple view of the money supply. They essentially equated the money supply with the amount of currency in circulation and the demand deposits held by the public in commercial banks.
The Role of the Central Bank and Commercial Banks
In the classical framework, the money supply was determined by:
- Base Money (High-Powered Money): This consisted of currency held by the public and reserves held by commercial banks at the central bank. The central bank had direct control over the base money supply.
- The Money Multiplier: Commercial banks played a crucial role. When people deposited money in banks, banks kept a fraction as reserves (required reserves) and lent out the rest. This lending process created new deposits, expanding the money supply. The ratio of reserves to deposits determined how much the money supply could expand from a given base of reserves.
The classical view often assumed that banks held only the minimum required reserves, and the public held a stable fraction of their money as currency versus demand deposits. This simplified the analysis of the money multiplier.
The Simplistic Classical Model
In its simplest form, the classical model assumed the money supply (M) was exogenous – meaning it was determined by external factors (like the central bank and banking system) and did not depend on the economic conditions like interest rates or income.
M = C + D Where:
- M is the total money supply.
- C is currency in circulation.
- D is demand deposits.
The focus was on the quantity of money available. Any increase in this quantity, given the assumptions about velocity and real output, would directly translate into higher prices. The supply side of money was not seen as being influenced by the demand for money or other economic variables in a complex feedback loop.
Summary Table: Key Differences
| Feature | Classical Approach | Keynesian Approach | Monetarist (Friedman) Approach |
|---|---|---|---|
| Primary Role of Money | Medium of Exchange | Medium of Exchange, Store of Value, Unit of Account | Medium of Exchange, Store of Value |
| Demand for Money Motives | Transactions | Transactions, Precautionary, Speculative | Transactions, Precautionary, Speculative (integrated into portfolio choice) |
| Determinants of Money Demand | Income (Y), Price Level (P) | Income (Y), Interest Rate (r) | Permanent Income (Yp), Interest Rate (r), Expected Inflation (πe) |
| Sensitivity to Interest Rates | Low/None | High (speculative demand) | Moderate (opportunity cost) |
| Impact of Money Supply on Economy | Affects Price Level (P) only (long run neutrality) | Affects Price Level (P), Output (Y), and Employment (in short run) via interest rates | Affects Nominal Income (P*Y); primarily P (inflation) in long run |
| Money Supply View | Exogenous, determined by currency and deposits | Can be influenced by central bank actions and banking system | Primarily exogenous, controllable by central bank, stable velocity |
| Key Equation | M*V = P*T (V, T constant) | Liquidity Preference (Ld=f(Y,r)) | M*V = P*Y (V stable, M controllable) |
Understanding these different perspectives is crucial for grasping how monetary policy is viewed and implemented in various economic schools of thought. Each approach offers insights into the complex relationship between money, prices, and real economic activity.