Presentation on theme: "AGGREGATE SUPPLY CHAPTER 9-2. AGGREGATE SUPPLY The aggregate supply curve shows the relationship between the aggregate price level and the quantity of."— Presentation transcript:
AGGREGATE SUPPLY The aggregate supply curve shows the relationship between the aggregate price level and the quantity of aggregate output.
AGGREGATE SUPPLY CURVE Aggregate Supply is the amount of real GDP that will be made available by sellers at various price levels. Aggregate Supply looks different in the Long Run and the Short Run: In the Long Run, classical economists assume the economy operates at full employment (maximum output), independent of the price level. In the Short Run, businesses will increase supply if the price level increases.
POSITIVE RELATIONSHIP There is a positive relationship in the short run between price level and the quantity of aggregate output supplied.
THE AGGREGATE SUPPLY CURVES The SAS curve is upward sloping because of: Auction markets Prices are determined by demand and supply and supply curves are upward sloping Posted price markets Also called quantity-adjusting markets, markets in which firms respond to changes in demand by changing production instead of changing their prices Firms tend to increase their markup when demand increases The Slope of the Short-Run Aggregate Supply (SAS) Curve
SHIFTS IN THE SAS CURVE Shifts in the SAS are caused by changes in: Input prices Productivity Import prices Excise and sales taxes When production costs increase, the SAS curve shifts up In general: %Δ in price level = %Δ in wages – %Δ in productivity SAS 0 Price level Real output SAS 1 SAS 2
THE LONG-RUN AGGREGATE SUPPLY CURVE The long-run aggregate supply (LAS) curve shows the long-run relationship between output and the price level The position of the LAS curve depends on potential output which is the amount of goods and services an economy can produce when both capital and labor are fully employed The LAS curve is vertical because potential output is unaffected by the price level
THE LAS CURVE Potential output is assumed to be in the middle of a range bounded by high and low levels of potential output LAS Price level Real output Low-level potential output High-level potential output SAS Underutilized resources Overutilized resources A B C When resources are over- utilized (point C), factor prices may be bid up and the SAS shifts up When resources are under- utilized (point A), factor prices may decrease and SAS shifts down
Real output Price Level Low-level potential output High-level potential output C SAS B A LAS Underutilized resources Overutilized resources Estimating potential output is inexact, so it is assumed to be the middle of a range bounded by a high level of potential output and a low level of potential output. The relationship between potential and actual output – where the economy is on SAS – determines shifts in SAS. When LAS = SAS (point B), there is no pressure for prices to rise or fall. When resources are over-utilized (point C), factor prices may be bid up and the SAS shifts up. When resources are under-utilized (point A), factor prices may decrease and SAS shifts down.
SHIFTS IN THE LAS CURVE Increases in the LAS are caused by increases in: Capital Resources Growth-compatible institutions Technology Entrepreneurship LAS 0 Price level Real output LAS 1 LAS 2
LRAS The long-run aggregate supply curve shows the relationship between the aggregate price level and the quantity of aggregate output supplied that would exist if all prices, including nominal wages, were fully flexible Do you remember the debate between Classical and Keynes?
A RANGE FOR POTENTIAL OUTPUT AND THE LAS CURVE The position of the long-run aggregate supply curve is determined by potential output. Potential output – the amount of goods and services an economy can produce when both labor and capital are fully employed. Was this in your textbook?
SHORT-RUN EQUILIBRIUM IN THE AD/AS MODEL Short-run equilibrium is where the SAS and AD curves intersect and point E is short-run equilibrium Price level Real output AD 0 P0P0 AD 1 P1P1 Y0Y0 Y1Y1 SAS A shift in the aggregate demand curve to the right changes equilibrium from E to F, increasing output from Y 0 to Y 1 and increasing price level from P 0 to P 1 E F
SHORT-RUN EQUILIBRIUM IN THE AD/AS MODEL Price level Real output AD P0P0 P2P2 Y0Y0 Y2Y2 SAS 1 A shift up in the short-run aggregate supply curve changes equilibrium from E to G, decreasing output from Y 0 to Y 2 and increasing price level from P 0 to P 2 SAS 0 E G
LONG-RUN EQUILIBRIUM IN THE AD/AS MODEL Long-run equilibrium is where the LAS and AD curves intersect Price level Real output AD 0 P0P0 AD 1 P1P1 YPYP LAS A shift in the aggregate demand curve changes equilibrium from E to H, increasing the price level from P 0 to P 1 but leaving output unchanged E H
APPLICATION: A RECESSIONARY GAP IN THE AD/AS MODEL A recessionary gap is the amount by which equilibrium output is below potential output Price level Real output P0P0 P1P1 YPYP LAS E SAS 0 SAS 1 AD 0 A Y1Y1 At point A, some resources are unemployed and the recessionary gap is Y P – Y 1 Gap Eventually wages and prices decrease and SAS shifts down to return the economy to a long and short-run equilibrium at E
APPLICATION: AN INFLATIONARY GAP IN THE AD/AS MODEL An inflationary gap is the amount by which equilibrium output is above potential output Price level Real output P0P0 P2P2 YPYP LAS E SAS 0 AD 0 Y2Y2 At point B, resources are being used beyond their potential and the inflationary gap is Y 2 – Y P SAS 2 B Gap Eventually wages and prices increase and SAS shifts to return the economy to a long and short-run equilibrium at E
FROM THE SHORT RUN TO THE LONG RUN Leftward Shift of the Short-run Aggregate Supply Curve
FROM THE SHORT RUN TO THE LONG RUN Rightward Shift of the Short-run Aggregate Supply Curve
AGGREGATE DEMAND POLICY A primary reason for government policy makers’ interest in the AS/AD model is that monetary or fiscal policy shifts the AD curve Monetary policy involves the Federal Reserve Bank changing the money supply and interest rates Fiscal policy is the deliberate change in either government spending or taxes to stimulate or slow down the economy
APPLICATION: EXPANSIONARY FISCAL POLICY IN THE AD/AS MODEL If the economy is at point A, there is a recessionary gap equal to Y P – Y 0 The appropriate fiscal policy is to increase government spending and/or decrease taxes AD shifts to the right and output returns to potential output Y P and prices increase to P 1 Price level Real output AD 0 P0P0 AD 1 P1P1 YPYP LAS A E Y0Y0 Gap
APPLICATION: CONTRACTIONARY FISCAL POLICY IN THE AD/AS MODEL If the economy is point B, there is an inflationary gap Y 2 – Y P The appropriate fiscal policy is to decrease government spending and/or increase taxes AD shifts to the left, output returns to potential output Y P and inflation is prevented Price level Real output AD 2 P1P1 AD 0 P2P2 YPYP LAS B E Y2Y2 Gap
LIMITATIONS OF THE AS/AD MODEL The AS/AD model assumes away many possible feedback effects that can significantly affect the macroeconomy and lead to quite different conclusions Implementing fiscal policy through changing taxes and government spending is a slow legislative process There is no guarantee that government will do what economists say is necessary
LIMITATIONS OF THE AS/AD MODEL Potential output (the level of output that the economy is capable of producing without generating inflation) is difficult to estimate We do have ways to get a rough idea of where it is There are many other possible interrelationships in the economy that the model does not take into account The aggregate economy can become dynamically unstable, so a shock can set in motion changes that will not automatically be self-correcting
LIMITATIONS OF THE AS/AD MODEL There are two ways to think about the effectiveness of fiscal policy: in the model and in reality The effectiveness of fiscal policy depends on the government’s ability to perceive and to react appropriately to a problem Countercyclical fiscal policy Countercyclical fiscal policy is fiscal policy in which the government offsets any change in aggregate expenditures that would create a business cycle Fine-tuning Fine-tuning is used to describe such fiscal policy designed to keep the economy always at its target or potential level of income
CHAPTER SUMMARY The key idea of the Keynesian AS/AD model is that in the short run the economy can deviate from potential output The AS/AD model consists of the aggregate demand curve, and the short-run aggregate supply curve, and the long-run aggregate supply curve Short-run equilibrium is where the SAS and AD curves intersect; Long-run equilibrium is where the AD and LAS curves intersect Aggregate demand management policy attempts to influence the level of output in the economy
CHAPTER SUMMARY Fiscal policy works by providing a deliberate countershock to offset unexpected shocks to the economy Macroeconomic policy is difficult to conduct because: Implementing fiscal policy is a slow process We don’t really know where potential output is There are interrelationships not included in the model The economy can become dynamically unstable