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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard Chapter 2 IS-LM Model Asst. Prof. Dr. Mete Feridun

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard The IS-LM Model The IS/LM model is a macroeconomic tool that demonstrates the relationship between interest rates and real output in the goods and services market and the money market. The IS/LM model is a macroeconomic tool that demonstrates the relationship between interest rates and real output in the goods and services market and the money market. The intersection of the IS and LM curves is the "General Equilibrium" where there is simultaneous equilibrium in both markets. The intersection of the IS and LM curves is the "General Equilibrium" where there is simultaneous equilibrium in both markets. IS/LM stands for Investment Saving / Liquidity preference Money supply. IS/LM stands for Investment Saving / Liquidity preference Money supply.

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard THE IS (Investment = Savings) CURVE Inflation and inflationary expectations are assumed to be stable. Inflation and inflationary expectations are assumed to be stable. The IS curve derives a relationship between interest rates and income in the short run An increase in the interest rate reduces investment by making it more expensive for firms to borrow money to make investment purchases and also by increasing the opportunity cost for those who plan to finance investment projects using their own funds.

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard the relationship between Y and r that ensure that the goods market is in equilibrium: spending=production. Note that when interest rates are high, investment falls and therefore Y must fall as well; the IS curve should show a negative relationship between r and Y.

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard Deriving the IS Curve Equilibrium in the goods market implies that an increase in the interest rate leads to a decrease in output. The IS curve is downward sloping. The Derivation of the IS Curve

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard a steep IS curve means that Y does not respond very much to r. In other words, a change in the real interest rate does not have a significant impact on GDP.

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard Movements Along the Curve When interest rates decrease, spending rises and as a result output increases as well. This is reflected in a movement to a lower point on the IS curve where interest rates are lower and output is higher. Conversely, when interest rates increase, spending falls and as a result output decreases as well. This is reflected in a movement to a higher point on the IS curve where interest rates are higher and output is lower.

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard Parallel Shifts of the IS Curve Increases in (1) consumer confidence, (2) investor confidence, (3) government purchases, (4) net exports will raise expenditure, and therefore production of goods and services, shifting the IS curve out (rightwards). A reduction in lump-sum taxes will increase expenditure on goods and services and therefore increase output as well. This will cause the IS curve to shift out.

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard Shifts of the IS Curve: T & G An increase in taxes shifts the IS curve to the left. Shifts of the IS Curve

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard IS Curve captures the effect of nominal interest rate i on output Y, for given values of T and G. (tax and government purchase). IS Curve captures the effect of nominal interest rate i on output Y, for given values of T and G. (tax and government purchase). Investment demand depends negative on interest rate. Hence, when i increase, the investment and then the total demand will fall. So will the total output Y. Investment demand depends negative on interest rate. Hence, when i increase, the investment and then the total demand will fall. So will the total output Y. Therefore, IS curve is downward sloping. Therefore, IS curve is downward sloping. The Goods Market and the IS Relation

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard We derived the IS curve, the first part of the model of economic fluctuations known as the IS-LM model. The IS Curve summarized all the combinations of interest rates and GDP that clear the market for goods and services in the economy. The IS curve by itself cannot give us the value of output in the economy because it does not have anything to say about the level of interest rates in the economy. Hence we need to derive the LM curve and study its intersection with the IS curve.

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard Financial Markets and Financial Markets and the LM (Liquidity Preference = Money Demand) curve LM curve is a relationship that describes the behavior of the money market, which determines interest rates in the economy. The LM curve consists of the combinations of income and interest rates that clear the market for money balances (i.e. equate money demand and money supply). The interest rate is determined by the equality of the supply of and the demand for money: The interest rate is determined by the equality of the supply of and the demand for money: M = nominal money stock $YL(i) = demand for money $Y = nominal income i = nominal interest rate

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard Real Money, Real Income, and the Interest Rate The LM relation: In equilibrium, the real money supply is equal to the real money demand, which depends on real income, Y, and the interest rate, I The LM relation: In equilibrium, the real money supply is equal to the real money demand, which depends on real income, Y, and the interest rate, I (Why? Because higher i implies a higher Opp. Cost of holding money). (Why? Because higher i implies a higher Opp. Cost of holding money). LM Curve captures the effect of output Y on nominal interest rate i, for given values of M (nominal money supply) and P (in short run price is assumed to be fixed).

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard When r is high, the demand for money is low because money pays no interest – the opportunity cost of holding money instead of other financial assets rises. When Y is high the demand for money is high, richer people who buy more goods are likely to hold more money. When prices P are high the demand for money is high since people need more money to complete their transactions. Higher total output implies higher transaction demand. So for given level of nominal money supply, high demand implies the interest rate that clear the money market has to increase. So when Y increases, the nominal interest rate i increases. Therefore, LM curve is upward sloping.

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard Deriving the LM Curve An increase in income leads, at a given interest rate, to an increase in the demand for money. Given the money supply, this leads to an increase in the equilibrium interest rate. The Effects of an Increase in Income on the Interest Rate

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard Deriving the LM Curve Equilibrium in financial markets implies that an increase in income leads to an increase in the interest rate. The LM curve is upward- sloping. The Derivation of the LM Curve

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard MOVEMENTS ALONG THE LM CURVE Changes in money demand brought about by changes in Y or by changes in r are reflected as movements along the LM curve. When income decreases, money demand falls and as a result interest rates must decrease to restore money market equilibrium. When income increases, money demand rises and as a result interest rates must increase to restore money market equilibrium.

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard If the CB increases the money supply (expansionary monetary policy) then from the equation we can see that the vertical (r) intercept will be lower and the horizontal (Y) intercept will be larger, i.e. the LM curve shifts out (to the right). An increase in the price level has the same effect as a decrease in the money supply - it shifts the LM curve in (to the left). An increase in exogenous money demand raises the vertical intercept and makes the horizontal intercept smaller: the LM curve shifts in (to the left).

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard The basic intuition is that the movement of interest rates depends on the relationship between money demand and money supply. Exogenous changes that bring about excess money demand, i.e. drive money demand above money supply, cause interest rates to rise in order to lower money demand and equilibrate money demand and supply. The LM curve will shift in. These changes include a fall in money supply, a rise in prices or an increase in exogenous money demand. Exogenous changes that bring about excess money supply, i.e. drive money supply above money demand cause interest rates to fall in order to raise money demand and equilibrate money demand and supply. The LM curve will shift out. These changes include an increase in money supply, a fall in prices or a decrease in exogenous money demand.

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard An increase in the supply of money by the CB will result in an excess supply of money. This will cause the LM curve to shift outwards in order to restore equilibrium. An increase in the price level will raise money demand and result in an excess demand for money. This will cause the LM curve to shift inwards to restore equilibrium

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard Another way of intuitively understanding the LM curve is as follows. When there is an excess supply of money, people are more likely to put the extra money into non monetary financial assets, so issuers of those assets can offer lower rates of interest yet still attract buyers. Conversely, when there is an excess demand for money, people are less likely to put money into non monetary financial assets, so issuers of those assets must offer higher rates of interest to attract buyers.

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard Shifts of the LM Curve: M An increase in money leads the LM curve to shift down. Shifts of the LM Curve

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard IS-LM model It is a short run model of the determination of output. The model has two main parts: an IS curve that summarizes all the combinations of Y and r consistent with goods market equilibrium and an LM curve that summarizes all the combinations of Y and r that are consistent with money market equilibrium. Since the IS curve summarizes all combinations of income and interest rates that clear the market for goods and services while the LM curve summarizes all combinations of income and interest rates that clear the money market, equilibrium income and the equilibrium interest rate are at the intersection of the two curves.

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard Putting the IS and the LM Relations Together Equilibrium in the goods market implies that an increase in the interest rate leads to a decrease in output. Equilibrium in financial markets implies that an increase in output leads to an increase in the interest rate. When the IS curve intersects the LM curve, both goods and financial markets are in equilibrium. The IS-LM Model

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard Anywhere other than the intersection we would expect there to be changes in Y or r that restore either goods market or money market equilibrium. Generally, we believe that the money market adjusts very quickly so the economy will rarely be off the LM curve. However, it will not stay off the IS curve for very long either as firms can adjust production to bring it in line with demand.

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard Fiscal Policy, Activity, and the Interest Rate Fiscal contraction, or fiscal consolidation, refers to fiscal policy that reduces the budget deficit. Fiscal contraction, or fiscal consolidation, refers to fiscal policy that reduces the budget deficit. An increase in the deficit is called a fiscal expansion. An increase in the deficit is called a fiscal expansion. Taxes affect the IS curve, not the LM curve. Taxes affect the IS curve, not the LM curve.

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard Fiscal Policy, Activity, and the Interest Rate An increase in taxes shifts the IS curve to the left, and leads to a decrease in the equilibrium level of output and the equilibrium interest rate. The Effects of an Increase in Taxes

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard Monetary Policy, Activity, and the Interest Rate Monetary contraction, or monetary tightening, refers to a decrease in the money supply. Monetary contraction, or monetary tightening, refers to a decrease in the money supply. An increase in the money supply is called monetary expansion. An increase in the money supply is called monetary expansion. Monetary policy does not affect the IS curve, only the LM curve. For example, an increase in the money supply shifts the LM curve down. Monetary policy does not affect the IS curve, only the LM curve. For example, an increase in the money supply shifts the LM curve down.

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard Monetary Policy, Activity, and the Interest Rate Monetary expansion leads to higher output and a lower interest rate. The Effects of a Monetary Expansion

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard Using a Policy Mix The combination of monetary and fiscal polices is known as the monetary-fiscal policy mix, or simply, the policy mix. The combination of monetary and fiscal polices is known as the monetary-fiscal policy mix, or simply, the policy mix. The Effects of Fiscal and Monetary Policy. Shift of IS Shift of LM Movement of Output Movement in Interest Rate Increase in taxesleftnonedown Decrease in taxesrightnoneup Increase in spendingrightnoneup Decrease in spendingleftnonedown Increase in moneynonedownupdown Decrease in moneynoneupdownup

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard The Clinton-Greenspan Policy Mix Selected Macro Variables for the United States, 1991-1998 19911992199319941995199619971998 Budget surplus (% of GDP) (minus sign = deficit) 3.3 4.5 3.8 2.7 2.4 1.4 0.3 0.8 GDP growth (%) 0.9 2.72.33.42.02.73.93.7 Interest rate (%)7.35.53.73.35.05.65.24.8

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard The Clinton-Greenspan Policy Mix The appropriate combination of deficit reduction and monetary expansion can achieve a reduction in the deficit without adverse effects on output. Deficit Reduction and Monetary Expansion

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard German Unification and the German Monetary-Fiscal Tug of War Table 5-2 Selected Macro Variables for West Germany, 1988- 1991 1991199219931994 GDP growth (%)3.73.84.53.1 Investment growth (%)5.98.510.56.7 Budget surplus (% of GDP) (minus sign = deficit) 2.1 0.2 1.8 2.9 Interest rate (%)4.37.18.59.2

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard German Unification and the German Monetary-Fiscal Tug of War The Monetary-Fiscal Policy Mix of Post- Unification Germany

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard Effects of Monetary and Fiscal Policy in the IS/LM Model Fiscal Policy Fiscal Policy Expansionary fiscal policy shifts the IS curve to the right Expansionary fiscal policy shifts the IS curve to the right Contractionary fiscal policy shifts the IS curve to the left Contractionary fiscal policy shifts the IS curve to the left Monetary Policy Monetary Policy Expansionary monetary policy shifts the LM curve to the right Expansionary monetary policy shifts the LM curve to the right Contractionary monetary policy shifts the LM curve to the left Contractionary monetary policy shifts the LM curve to the left

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard Fiscal Policy and Crowding Out When government expenditures increase, output and income begin to increase. When government expenditures increase, output and income begin to increase. The increase in income increases the demand for money. The increase in income increases the demand for money. The increase in money demand increases the interest rate. The increase in money demand increases the interest rate. Higher interest rates cause a decrease in investment, offsetting some of the expansionary effect of the increase in government spending. Higher interest rates cause a decrease in investment, offsetting some of the expansionary effect of the increase in government spending.

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard Partial Crowding Out 1. Lets assume if government spending increases by $500, IS increases by $1000. $6600 IS 0 LM Real Interest Rate (%) Aggregate Output IS 1 $1000 4% $6000 5% $7000 2. The increase in income increases money demand which increases interest rates from 4% to 5%. 3. The increase in the interest rate causes a decrease in investment so that the increase in income is only $600, less that the full multiplier effect.

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard Full Crowding Out 1. Again government spending increases by $500, and the IS increases by $1000. 2. If the demand for money is totally insensitive to the interest rate, the interest rate increases from 4% to 9%. 3. The increase in the interest rate causes a decrease in investment that completely offsets the increase in government spending. IS 0 LM Real Interest Rate (%) Aggregate Output IS 1 $1000 4% $6000 9% $7000

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard Ineffective Fiscal Policy When complete crowding out occurs, fiscal policy is ineffective, changing only interest rates, not output. When complete crowding out occurs, fiscal policy is ineffective, changing only interest rates, not output. Crowding out is greater if: Crowding out is greater if: Money demand is very sensitive to income changes Money demand is very sensitive to income changes Money demand is not very sensitive to interest rate changes Money demand is not very sensitive to interest rate changes

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard Monetary Policy in the IS/LM Model In a liquidity trap, increases in the money supply do not decrease interest rates, so investment and output do not increase. The CB increases the money supply which decreases interest rates and increases investment and output. Y1Y1 IS LM 0 Real Interest Rate (%) Aggregate Output Y0Y0 r0r0 r1r1 LM 1 IS LM 0 Real Interest Rate (%) Aggregate Output Y0Y0 r0r0 LM 1

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard Ineffective Monetary Policy Investment is not sensitive to the interest rate Investment is not sensitive to the interest rate If investment does not respond to interest rate changes (the IS curve is steep), monetary policy in ineffective in changing output. If investment does not respond to interest rate changes (the IS curve is steep), monetary policy in ineffective in changing output. Liquidity trap Liquidity trap If increases in the money supply fail to lower interest rates, monetary policy is ineffective in increasing output. If increases in the money supply fail to lower interest rates, monetary policy is ineffective in increasing output.

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard Short-Run Outcomes of Policy

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard Examples of Monetary and Fiscal Policies

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard Anticipation of Policy Problems The IS/LM model does not take into account the effect of peoples expectations of policy actions. The IS/LM model does not take into account the effect of peoples expectations of policy actions. If investors expect the Fed to increase the money supply and decrease interest rates, they will buy bonds now. If investors expect the Fed to increase the money supply and decrease interest rates, they will buy bonds now. The increase in demand for bonds increases their price and decreases interest rates before the money supply is actually increased. The increase in demand for bonds increases their price and decreases interest rates before the money supply is actually increased.

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard Monetary Policy Tools and Credit Condition Problems The IS/LM model assumes that interest rates are the only determinant of investment. The IS/LM model assumes that interest rates are the only determinant of investment. Investment also depends on credit conditions, the willingness of banks to lend independent of interest rates. Investment also depends on credit conditions, the willingness of banks to lend independent of interest rates. If banks raise their lending standards, investment may not respond to expansionary monetary policy. If banks raise their lending standards, investment may not respond to expansionary monetary policy.

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard Implementation Problems of Monetary and Fiscal Policy Uncertainty about Potential Output Uncertainty about Potential Output Information Lag Information Lag Policy Implementation Lag Policy Implementation Lag

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard Uncertainty About Potential Output One macroeconomic policy goal is to keep output as close to potential as possible. One macroeconomic policy goal is to keep output as close to potential as possible. In the real world, economists arent sure what potential output is. In the real world, economists arent sure what potential output is. If policymakers use contractionary policy when the economy is actually below potential, they create unemployment. If policymakers use contractionary policy when the economy is actually below potential, they create unemployment. Using expansionary policy above potential output will cause inflation. Using expansionary policy above potential output will cause inflation.

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard Information Lag The IS/LM model assumes that policymakers see what is happening in the economy and can instantly alter policies to fix any problem. The IS/LM model assumes that policymakers see what is happening in the economy and can instantly alter policies to fix any problem. In the real world there is an information lag, a delay between a change in the economy and knowledge of that change. In the real world there is an information lag, a delay between a change in the economy and knowledge of that change.

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard Policy Implementation Lag The policy implementation lag is the delay between the time policymakers recognize the need for a policy action and when the policy is instituted. The policy implementation lag is the delay between the time policymakers recognize the need for a policy action and when the policy is instituted. Fiscal policy has a large implementation lag because policy must be formulated and legislation passed by Congress and the President. Fiscal policy has a large implementation lag because policy must be formulated and legislation passed by Congress and the President. Monetary policy has a shorter implementation lag because the Federal Open Market Committee decides monetary policy. Monetary policy has a shorter implementation lag because the Federal Open Market Committee decides monetary policy.

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© 2003 Prentice Hall Business PublishingMacroeconomics, 3/e Olivier Blanchard

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