In-Depth Notes on Short-Run Aggregate Supply Curve and Economic Shifts

Short-Run Aggregate Supply Curve (SRAS)

  • Definition: SRAS illustrates the connection between total planned economy-wide production and the price level in the short run, holding all other factors constant.
    • Positively Sloped Curve: Incomplete price adjustments in the short run imply that the SRAS curve slopes upward.

Key Characteristics of SRAS

  • Partial Price Adjustment: Modern Keynesian analysis acknowledges partial adjustments in prices; some are flexible in the short run.
  • Steeper Slope: After intersecting with Long-Run Aggregate Supply (LRAS), the SRAS slope becomes steeper as firms require higher prices to increase production temporarily beyond full-employment real GDP.

Changes in Aggregate Demand

  • An upward shift in aggregate demand results in higher equilibrium real GDP and price levels.
    • Example: If Aggregate Demand increases from AD1 to AD2, equilibrium real GDP rises to $22.5 trillion, but with a price level increase to 120, some planned purchases decline.

Factors Behind the Upward Slope of SRAS

  1. Labor Utilization:
    • Workers may be asked to work more intensively (additional hours/days).
  2. Capital Equipment:
    • Existing machinery may be used more intensively or operated at higher rates, potentially postponing maintenance.
  3. Wage Rate Effects:
    • If wages remain constant, increased production at higher prices can boost profits, leading firms to hire more labor.
    • Declining unemployment rates as previously non-participating individuals enter the workforce.

Shifts in the Aggregate Supply Curve

  • Non-price-level factors can shift both SRAS and LRAS, more complex and varied than aggregate demand shifts.
  • Key Events Causing Shifts:
    • Changes in factors of production (labor, capital, technology) that influence economic growth can shift both SRAS and LRAS curves.
Example of Permanent Shifts
  • Loss of Production Resources: A significant event causing a permanent loss (e.g., a major oil spill) shifts LRAS leftward and may also shift SRAS leftward but does not restore to initial states.
Temporary Shifts
  • Input Price Changes: Temporary fluctuations in input prices (such as an oil price hike due to a natural disaster) will shift SRAS without affecting LRAS.

Effects of Aggregate Demand and Supply Shocks

  • Aggregate Demand Shock: Any event causing shifts in aggregate demand.
  • Aggregate Supply Shock: Any event leading to shifts in aggregate supply.
  • Short-Run Adjustments: Changes due to shocks may lead to variations in equilibrium price or GDP, highlighting both upward and downward pressures in scenarios where demand declines or increases.

Aggregate Demand Changes

When Demand Falls (Stable Supply)
  • Outcome: A decrease in aggregate demand leads to rising unemployment rates.
    • Example: Shift to a new aggregate demand curve (AD2) results in a recessionary gap, with real GDP less than the long-run potential.
When Demand Increases
  • Outcome: An increase in demand shifts equilibrium upward, potentially leading to inflation and pressures on prices.