清华经济学原理28货币和财政政策对总需求的影响

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货币政策如何影响总需求 How Monetary Policy Influences Aggregate Demand
在长期中，美联储控制的货币供给影响物 价水平。 In the long run, the money supply controlled by the Fed affects the price level. 在短期中，货币政策影响总需求，进而影 响产出等宏观经济变量。 In the short run, monetary policy tools can shift the aggregate-demand curve and, in doing so, affect macroeconomic variables as output.
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货币市场与总需求曲线的斜率 The Money Market and the Slope of the Aggregate Demand Curve...
(a) 货币市场 The Money Market
Interest Rate
Money supply
(b) 总需求曲线 The Aggregate Demand Curve Price Level
Money demand 货币需求 Quantity of Money货币量
应用：总需求曲线向下倾斜 Application: The Downward Slope of the Aggregate Demand Curve


回顾：总需求曲线向下倾斜有三个原因。 The aggregate demand curve slopes downward for three reasons: 财富效应 The wealth effect 利率效应 The interest-rate effect 汇率效应 The exchange-rate effect 对美国经济来说，总需求曲线向下倾斜的最重要原 因是利率效应。 For the U.S. economy, the most important reason for the downward slope of the aggregate-demand curve is the interest-rate effect.
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Quantity fixed by the Fed
Quantity of Money
0
Y2
Y1 Quantity of Output
3. …提高了均衡利率 which increases the equilibrium interest rate…
4. …这又减少了物品与服务的需求量 which in turn reduces the quantity of goods and services demanded.
货币政策与财政政策对总需求的影响 The Influence of Monetary and Fiscal Policy on Aggregate Demand
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Fra Baidu bibliotek
总需求 Aggregate Demand
除了货币与财政政策以外，有许多 因素影响总需求。 Many factors influence aggregate demand besides monetary and fiscal policy. 特别的，家庭与企业希望的支出决 定了对于物品与服务的总体需求。 In particular, desired spending by households and business firms determines the overall demand for goods and services.

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货币需求 Money Demand




人们选择持有货币而不是带来更高回报率的其他资产， 是因为货币能够用来购买物品与服务。 People choose to hold money instead of other assets that offer higher rates of return because money can be used to buy goods and services. 持有货币的机会成本，是从有利息收益的资产中能够得 到的利息。 The opportunity cost of holding money is the interest that could be earned on interest-earning assets. 利率上升，提高了持有货币的机会成本。 An increase in the interest rate raises the opportunity cost of holding money. 结果，货币需求数量下降了。 As a result, the quantity of money demanded is reduced.


通过利率效应 through the interest-effect
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流动性偏好理论 The Theory of Liquidity Preference



凯恩斯发展了流动性偏好理论，以解释决定经济的利 率的因素。 Keynes developed the theory of liquidity preference in order to explain what factors determine the economy’s interest rate. 按照这一理论，利率调整以平衡货币供求。 According to the theory, the interest rate adjusts to balance the supply and demand for money. 流动性偏好理论试图同时解释名义和实际两种利率， 只需要假定通胀率不变。 Liquidity preference theory attempts to explain both nominal and real rates by holding constant the rate of inflation. 5

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总需求 Aggregate Demand
当希望的支出改变，总需求移动，导致短期 产出与就业的波动。 When desired spending changes, aggregate demand shifts, causing short-run fluctuations in output and employment. 货币与财政政策有时能用以弥补这些移动， 稳定经济。 Monetary and fiscal policy are sometimes used to offset those shifts and stabilize the economy.
货币供给 Money Supply
货币供给由中央银行（美国为Fed）
通过以下途径进行控制： The money supply is controlled by the Fed through:
公开市场运作 Open-market operations 改变法定准备金 Changing the reserve requirements 改变贴现率 Changing the discount rate

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货币需求 Money Demand
货币需求决定于若干因素。 Money demand is determined by several factors. 按照流动性偏好理论，最为重要的因素之一 是利率。 According to the theory of liquidity preference, one of the most important factors is the interest rate.
1. 价格水平的上升 An increase in the price level…
r2 r1
2. …增加了货币需 求increases the demand for money…
P2
Aggregate demand
Money demand at price level P2, MD2
P1
Money demand at price level P1, MD1
应用：总需求曲线向下倾斜 Application: The Downward Slope of the Aggregate Demand Curve
这一分析的最终结果是：价格水平 与物品及服务的需求量的负向关系 The end result of this analysis is a negative relationship between the price level and the quantity of goods and services demanded.
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货币市场均衡 Equilibrium in the Money Market

按照流动性偏好理论： According to the theory of liquidity preference:


利率调整以平衡货币的供求。 The interest rate adjusts to balance the supply and demand for money. 在均衡利率下，货币供求平衡。 There is one interest rate, called the equilibrium interest rate, at which the quantity of money demanded equals the quantity of money supplied.
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货币供给的改变 Changes in the Money Supply




央行在改变货币政策时，能够移动总需求曲线。 The Fed can shift the aggregate demand curve when it changes monetary policy. 货币供给的增加将货币供给曲线向右移动。 An increase in the money supply shifts the money supply curve to the right. 如果货币需求曲线没有变动，利率就会下降。 Without a change in the money demand curve, the interest rate falls. 利率的下降增加了物品与服务的需求量。 Falling interest rates increase the quantity of goods and services demanded.
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应用：总需求曲线向下倾斜 Application: The Downward Slope of the Aggregate Demand Curve




价格水平是货币需求量的一个决定因素。 The price level is one determinant of the quantity of money demanded. 更高的价格水平增加了给定利率下货币的需求量 A higher price level increases the quantity of money demanded for any given interest rate. 更高的货币需求导致更高的利率。 Higher money demand leads to a higher interest rate. 物品与服务的需求量下降。 The quantity of goods and services demanded 13 falls.
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货币市场均衡 Equilibrium in the Money Market...
Interest Rate 利率
Money supply 货币供给
r1
Equilibrium interest rate 均衡利率
r2
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d M1 d Quantity fixed M2 by the Fed央行固定量

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货币供给 Money Supply
货币供给的数量不依赖于利率，因为它被 美联储（央行）固定住了。 Because it is fixed by the Fed, the quantity of money supplied does not depend on the interest rate. 固定的货币供给用一条垂直的供给曲线来 表示。 The fixed money supply is represented by a vertical supply curve.