1 U D T E S E V E N T H E D I T I O N /15/11 MCROECONOMICS N. Gregory Mankiw oweroint Slides by Ron Cronovich C H T E R 9 Introduction to Economic Fluctuations In this chapter, you will learn: facts about the business cycle how the short run differs from the long run an introduction to aggregate demand an introduction to aggregate supply in the short run and long run how the model of aggregate demand and aggregate supply can be used to analyze the short-run and long-run effects of shocks. 11 Worth ublishers, all rights reserved Facts about the business cycle GD growth averages 3 3.5 percent per year over the long run with large fluctuations in the short run. Consumption and investment fluctuate with GD, but consumption tends to be less volatile and investment more volatile than GD. Unemployment rises during recessions and falls during expansions. Okun s Law: the negative relationship between GD and unemployment. Growth rates of real GD, consumption ercent change from quarters earlier verage growth rate - Real GD Consumption - 197 1975 19 195 199 1995 5 Growth rates of real GD, consump., investment Unemployment ercent change from quarters earlier 3 Investment ercent of labor force 1 Real GD - Consumption - -3 197 1975 19 195 199 1995 5 197 1975 19 195 199 1995 5 1
= /15/11 Okun s Law ercentage change in real GD 19 1951 19 197 3 u 3 1971 Index of Leading Economic Indicators ublished monthly by the Conference oard. ims to forecast changes in economic activity -9 months into the future. Used in planning by businesses and govt, despite not being a perfect predictor. - 1 1991 19 1975 - -3 - -1 1 3 Change in unemployment rate 7 Components of the LEI index verage workweek in manufacturing Initial weekly claims for unemployment insurance New orders for consumer goods and materials New orders, nondefense capital goods Vendor performance New building permits issued Index of stock prices M ield spread (-year minus 3-month) on Treasuries Index of consumer expectations Index of Leading Economic Indicators, 197-1 1 9 7 5 3 Source: Conference 197 oard 1975 19 195 199 1995 5 Time horizons in macroeconomics Long run rices are flexible, respond to changes in supply or demand. Short run Many prices are sticky at a predetermined level. The economy behaves much differently when prices are sticky. Recap of classical macro theory (Chaps. 3-) Output is determined by the supply side: supplies of capital, labor technology Changes in demand for goods & services (C, I, G ) only affect prices, not quantities. ssumes complete price flexibility. pplies to the long run. 11
/15/11 When prices are sticky output and employment also depend on demand, which is affected by: fiscal policy (G and T ) monetary policy (M ) other factors, like exogenous changes in C or I The model of aggregate demand and supply The paradigm most mainstream economists and policymakers use to think about economic fluctuations and policies to stabilize the economy Shows how the price level and aggregate output are determined Shows how the economy s behavior is different in the short run and long run 1 13 ggregate demand The aggregate demand curve shows the relationship between the price level and the quantity of output demanded. For this chapter s intro to the D/S model, we use a simple theory of aggregate demand based on the quantity theory of money. Chapters -1 develop the theory of aggregate demand in more detail. The Quantity Equation as ggregate Demand From Chapter, recall the quantity equation MV = For given values of M and V, this equation implies an inverse relationship between and 1 15 The downward-sloping D curve Shifting the D curve n increase in the price level causes a fall in real money balances (M/ ), causing a decrease in the demand for goods & services. D n increase in the money supply shifts the D curve to the right. 1 17 3
/15/11 ggregate supply in the long run The long-run aggregate supply curve Recall from Chapter 3: In the long run, output is determined by factor supplies and technology F ( K, L) is the full-employment or natural level of output, at which the economy s resources are fully employed. Full employment means that unemployment equals its natural rate (not zero). 1 does not depend on, so is vertical. F ( K, L) 19 Long-run effects of an increase in M ggregate supply in the short run In the long run, this raises the price level but leaves output the same. 1 n increase in M shifts D to the right. Many prices are sticky in the short run. For now (and through Chap. 1), we assume all prices are stuck at a predetermined level in the short run. firms are willing to sell as much at that price level as their customers are willing to buy. Therefore, the short-run aggregate supply (SRS) curve is horizontal: 1 The short-run aggregate supply curve Short-run effects of an increase in M The SRS curve is horizontal: The price level is fixed at a predetermined level, and firms sell as much as buyers demand. SRS In the short run when prices are sticky, causes output to rise. 1 an increase in aggregate demand SRS 3
/15/11 From the short run to the long run The SR & LR effects of M > Over time, prices gradually become unstuck. When they do, will they rise or fall? In the short-run equilibrium, if then over time, will rise fall remain constant The adjustment of prices is what moves the economy to its long-run equilibrium. = initial equilibrium = new shortrun eq m after Fed increases M C = long-run equilibrium C SRS 5 How shocking!!! The effects of a negative demand shock shocks: exogenous changes in agg. supply or demand Shocks temporarily push the economy away from full employment. Example: exogenous decrease in velocity If the money supply is held constant, a decrease in V means people will be using their money in fewer transactions, causing a decrease in demand for goods and services. D shifts left, depressing output and employment in the short run. Over time, prices fall and the economy moves down its demand curve toward fullemployment. C SRS 7 Supply shocks supply shock alters production costs, affects the prices that firms charge. (also called price shocks) Examples of adverse supply shocks: ad weather reduces crop yields, pushing up food prices. Workers unionize, negotiate wage increases. New environmental regulations require firms to reduce emissions. Firms charge higher prices to help cover the costs of compliance. Favorable supply shocks lower costs and prices. CSE STUD: Early 197s: OEC coordinates a reduction in the supply of oil. Oil prices rose 11% in 1973 % in 197 1% in 1975 Such sharp oil price increases are supply shocks because they significantly impact production costs and prices. 9 5
/15/11 CSE STUD: The oil price shock shifts SRS up, causing output and employment to fall. In absence of further price shocks, prices will fall over time and economy moves back toward full employment. 1 SRS SRS 1 D 3 CSE STUD: redicted effects of the oil shock: inflation output unemployment and then a % gradual recovery. % 7% % 5% % 3% % % 1973 197 1975 197 1977 Change in oil prices (left scale) Inflation rate-ci (right scale) Unemployment rate (right scale) 1% % % % 31 CSE STUD: Late 197s: s economy was recovering, oil prices shot up again, causing another huge supply shock!!! % 5% % 3% % % % 1977 197 1979 19 191 Change in oil prices (left scale) Inflation rate-ci (right scale) Unemployment rate (right scale) 1% 1% % % % % 3 CSE STUD: The 19s oil shocks 19s: favorable supply shock-- a significant fall in oil prices. s the model predicts, inflation and unemployment fell: % 3% % % % -% -% -3% -% -5% 19 193 19 195 19 197 Change in oil prices (left scale) Inflation rate-ci (right scale) Unemployment rate (right scale) % % % % % % 33 Stabilization policy def: policy actions aimed at reducing the severity of short-run economic fluctuations. Example: Using monetary policy to combat the effects of adverse supply shocks Stabilizing output with monetary policy The adverse supply shock moves the economy to point. 1 SRS SRS 1 3 35
/15/11 Stabilizing output with monetary policy ut the Fed accommodates the shock by raising agg. demand. results: is permanently higher, but remains at its fullemployment level. 1 C SRS Chapter Summary 1. Long run: prices are flexible, output and employment are always at their natural rates, and the classical theory applies. Short run: prices are sticky, shocks can push output and employment away from their natural rates.. ggregate demand and supply: a framework to analyze economic fluctuations 3 Chapter Summary 3. The aggregate demand curve slopes downward.. The long-run aggregate supply curve is vertical, because output depends on technology and factor supplies, but not prices. 5. The short-run aggregate supply curve is horizontal, because prices are sticky at predetermined levels. Chapter Summary. Shocks to aggregate demand and supply cause fluctuations in GD and employment in the short run. 7. The Fed can attempt to stabilize the economy with monetary policy. 7