💲Honors Economics Unit 11 – Aggregate Demand and Aggregate Supply

Key Concepts and Definitions

• Aggregate demand (AD) represents the total demand for goods and services in an economy at a given price level
• Aggregate supply (AS) represents the total supply of goods and services in an economy at a given price level
• Macroeconomic equilibrium occurs when aggregate demand equals aggregate supply, determining the overall price level and real GDP
• Short-run aggregate supply (SRAS) refers to the total supply of goods and services in the short term, holding some factors constant (e.g., capital, technology)
• Long-run aggregate supply (LRAS) represents the total supply of goods and services in the long term, allowing all factors to adjust (e.g., capital, labor, technology)
• Sticky prices and wages are slow to adjust to changes in economic conditions, affecting the shape of the SRAS curve
• Potential output (or full-employment output) is the maximum sustainable level of real GDP an economy can produce when all resources are fully employed

Components of Aggregate Demand

• Consumption (C) includes spending by households on goods and services (e.g., food, clothing, entertainment)
  • Disposable income, consumer confidence, and wealth affect consumption levels
• Investment (I) consists of spending by businesses on capital goods (e.g., machinery, equipment, buildings)
  • Interest rates, expected future profits, and technological advancements influence investment decisions
• Government spending (G) encompasses expenditures by federal, state, and local governments on goods and services (e.g., infrastructure, defense, education)
• Net exports (NX) represent the difference between a country's exports and imports of goods and services
  • Exchange rates, foreign income levels, and trade policies impact net exports
• The AD curve shows the relationship between the price level and the quantity of goods and services demanded, holding other factors constant
• Changes in any of the components of AD (C, I, G, or NX) can shift the AD curve to the right (increase in AD) or left (decrease in AD)

Factors Affecting Aggregate Demand

• Changes in consumer confidence or expectations about future economic conditions can shift the AD curve
  • Optimistic consumers tend to spend more, shifting AD to the right, while pessimistic consumers may save more, shifting AD to the left
• Fiscal policy, including changes in government spending and taxation, can impact AD
  • Expansionary fiscal policy (increased spending or reduced taxes) shifts AD to the right, while contractionary fiscal policy (decreased spending or increased taxes) shifts AD to the left
• Monetary policy, controlled by the central bank, affects interest rates and the money supply, influencing AD
  • Expansionary monetary policy (lower interest rates or increased money supply) shifts AD to the right, while contractionary monetary policy (higher interest rates or decreased money supply) shifts AD to the left
• Changes in the exchange rate can affect net exports and, consequently, AD
  • A depreciation of the domestic currency makes exports more competitive and imports more expensive, shifting AD to the right, while an appreciation has the opposite effect
• Wealth effects, such as changes in stock prices or housing values, can impact consumption and AD
  • Positive wealth effects (e.g., rising stock prices) can increase consumption and shift AD to the right, while negative wealth effects have the opposite impact

Understanding Aggregate Supply

• The AS curve represents the relationship between the price level and the quantity of goods and services supplied in an economy
• The shape of the AS curve differs in the short run and the long run due to the flexibility of input prices and the adjustment of economic factors
• In the short run, the SRAS curve is upward sloping, reflecting the gradual adjustment of input prices and the presence of sticky prices and wages
• Factors that can shift the SRAS curve include changes in input prices (e.g., raw materials, energy), productivity, and government regulations
  • An increase in input prices or stricter regulations shifts the SRAS curve to the left, while a decrease in input prices or deregulation shifts the SRAS curve to the right
• In the long run, the LRAS curve is vertical at the potential output level, as all factors of production are fully adjusted and flexible
• The LRAS curve can shift due to changes in factors such as the quantity and quality of labor, capital stock, natural resources, and technology
  • Improvements in these factors shift the LRAS curve to the right, while deterioration shifts the LRAS curve to the left

Short-Run vs. Long-Run Aggregate Supply

• The short-run aggregate supply (SRAS) curve is upward sloping due to the gradual adjustment of input prices and the presence of sticky prices and wages
  • In the short run, firms may respond to increased demand by increasing output without fully adjusting prices, leading to a movement along the SRAS curve
• The long-run aggregate supply (LRAS) curve is vertical at the potential output level, as all factors of production are fully adjusted and flexible in the long run
  • In the long run, changes in aggregate demand only affect the price level, not real GDP, as the economy adjusts to its potential output
• The economy may deviate from its potential output in the short run due to various shocks or policy changes, but it tends to return to long-run equilibrium over time
• The transition from short-run to long-run equilibrium involves changes in input prices, wages, and other economic factors, which gradually adjust to the new economic conditions
• Supply shocks, such as changes in oil prices or natural disasters, can shift the SRAS curve and cause short-run fluctuations in output and prices
  • Positive supply shocks shift the SRAS curve to the right, while negative supply shocks shift the SRAS curve to the left

Equilibrium and Economic Fluctuations

• Macroeconomic equilibrium occurs when aggregate demand (AD) equals aggregate supply (AS) at the intersection of the AD and AS curves
• Short-run equilibrium is determined by the intersection of the AD curve and the SRAS curve, while long-run equilibrium is determined by the intersection of the AD curve and the LRAS curve
• Changes in AD or AS can lead to economic fluctuations and shifts in the equilibrium price level and real GDP
• Inflationary gaps occur when AD exceeds AS at the potential output level, leading to demand-pull inflation
  • To close an inflationary gap, policymakers may use contractionary fiscal or monetary policy to reduce AD
• Recessionary gaps occur when AD is insufficient to maintain the potential output level, leading to unemployment and unused capacity
  • To close a recessionary gap, policymakers may use expansionary fiscal or monetary policy to increase AD
• Stagflation is a situation characterized by high inflation and high unemployment, often caused by adverse supply shocks that shift the SRAS curve to the left
• Economic fluctuations can be caused by various factors, such as changes in consumer confidence, investment spending, government policies, or external shocks (e.g., oil price changes)

Policy Implications and Interventions

• Fiscal policy involves the use of government spending and taxation to influence AD and stabilize the economy
  • Expansionary fiscal policy (increased spending or reduced taxes) can be used to stimulate the economy during a recession by increasing AD
  • Contractionary fiscal policy (decreased spending or increased taxes) can be used to combat inflation by reducing AD
• Monetary policy involves the central bank's use of tools such as interest rates and the money supply to influence AD and maintain price stability
  • Expansionary monetary policy (lower interest rates or increased money supply) can stimulate the economy by encouraging borrowing and spending, shifting AD to the right
  • Contractionary monetary policy (higher interest rates or decreased money supply) can combat inflation by reducing borrowing and spending, shifting AD to the left
• Supply-side policies aim to increase productivity, efficiency, and the economy's potential output by improving factors that affect LRAS
  • Examples include investments in education and training, research and development, infrastructure, and deregulation
• Policymakers face the challenge of finding the right balance between short-run stabilization and long-run economic growth
  • Time lags in the implementation and impact of policies can make it difficult to achieve desired outcomes
• The effectiveness of policy interventions depends on various factors, such as the size and timing of the intervention, the state of the economy, and the credibility of the policymakers

Real-World Applications and Case Studies

• The Great Recession (2007-2009) was characterized by a significant decline in AD due to a housing market crash and financial crisis
  • Governments and central banks responded with expansionary fiscal and monetary policies to stimulate the economy and prevent a deeper recession
• The COVID-19 pandemic (2020-2021) caused both demand and supply shocks, leading to a global economic downturn
  • Governments implemented large-scale fiscal stimulus packages and central banks pursued accommodative monetary policies to support the economy
• The oil price shocks of the 1970s led to stagflation, as the sharp increase in energy costs shifted the SRAS curve to the left, causing both high inflation and high unemployment
• Japan's "Lost Decade" (1990s) was characterized by prolonged economic stagnation, deflation, and a liquidity trap, despite expansionary monetary policy efforts
  • Structural issues, such as an aging population and a lack of productivity growth, contributed to the economy's slow recovery
• The European debt crisis (2010-2012) highlighted the challenges of conducting monetary policy in a currency union with diverse economic conditions
  • The European Central Bank faced the task of balancing the needs of countries with high debt levels and those with more stable economies