Shifts in Aggregate Supply Study Pack

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Last updated May 21, 2026

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Shifts in Aggregate Supply Study Guide

Unpack the forces that shift aggregate supply in both the short run and long run, from sticky wages and energy price spikes to productivity gains and government policy. This pack covers SRAS and LRAS mechanics, key shifters like input costs and technology, and real-world events such as supply shocks and stagflation — everything you need to master this core macroeconomics topic.

Key Takeaways

  • •Aggregate supply represents the total quantity of goods and services that all firms in an economy are willing and able to produce at various price levels, and its curve can shift left or right when underlying production conditions change.
  • •The long-run aggregate supply (LRAS) curve is vertical at the potential GDP level, reflecting the economy's maximum sustainable output determined by available resources and technology, not by the price level.
  • •The short-run aggregate supply (SRAS) curve slopes upward because input costs — particularly wages — are "sticky" and adjust slowly, allowing higher price levels to temporarily boost output and profit margins.
  • •Changes in input costs, especially wages and energy prices, are among the most powerful shifters of SRAS: a rise in input costs shifts SRAS leftward (decreasing supply), while a fall shifts it rightward (increasing supply).
  • •Improvements in productivity and technology shift both SRAS and LRAS rightward by allowing the same inputs to produce more output at lower per-unit cost.
  • •Government policies — including changes in tax rates on businesses, subsidies, and regulations — affect production costs and can shift aggregate supply in either direction.
  • •Supply shocks, such as a sudden spike in oil prices or a natural disaster, cause abrupt leftward shifts in SRAS and can trigger stagflation, a simultaneous rise in the price level and fall in real GDP.

Two Versions of Aggregate Supply: Short Run vs. Long Run

Aggregate supply is not a single, uniform concept — economists distinguish between short-run and long-run versions because the economy behaves very differently depending on whether prices and wages have had time to fully adjust.

Long-Run Aggregate Supply (LRAS)

  • •LRAS is a vertical line drawn at the economy's potential GDP, the output level achievable when all resources — labor, capital, and land — are fully and efficiently employed.
  • •Because LRAS is vertical, changes in the price level alone do not affect long-run output; only real factors such as the size of the labor force, the capital stock, or technology determine where LRAS sits.
  • •Potential GDP grows over time as an economy accumulates capital, expands its workforce, or adopts better technology, shifting LRAS rightward.

Short-Run Aggregate Supply (SRAS)

  • •SRAS slopes upward because many input costs, especially wages set in multi-year contracts, do not instantly rise when the overall price level increases, so higher output prices temporarily widen firms' profit margins and encourage greater production.
  • •This wage and price stickiness means that in the short run, the economy can produce above or below its potential GDP — conditions that eventually self-correct as wages and other costs catch up to the price level.
  • •The gap between actual output and potential GDP is called the output gap; a positive gap (boom) puts upward pressure on wages, while a negative gap (recession) puts downward pressure.

Input Costs as the Primary Driver of SRAS Shifts

Because SRAS is built on the relationship between output prices and production costs, anything that changes the cost of inputs — without a corresponding change in output prices — will shift the entire SRAS curve.

Wages and Labor Costs

  • •Wages are the single largest input cost for most firms; when wages rise faster than productivity, per-unit production costs increase, causing firms to supply less at every price level and shifting SRAS leftward.
  • •Conversely, slower wage growth or an increase in the available labor supply reduces per-unit labor costs and shifts SRAS rightward.
  • •Collective bargaining outcomes, minimum wage legislation, and labor market conditions all influence wage levels and therefore SRAS.

Energy and Raw Material Prices

  • •Energy prices — particularly oil — feed into the cost of manufacturing, transportation, and heating, making them a pervasive cost input across industries.
  • •A sharp rise in oil prices, such as occurred during the 1970s OPEC embargo, raises costs economy-wide, shifting SRAS leftward and producing stagflation — a combination of higher prices and lower real output.
  • •Falling commodity prices have the opposite effect, reducing production costs and shifting SRAS rightward.

Other Input Prices

  • •The prices of raw materials such as steel, lumber, and agricultural commodities affect SRAS in the industries that depend on them and can ripple through supply chains.
  • •Import prices also function as input costs; a depreciation of the domestic currency raises the cost of imported inputs and can shift SRAS leftward.

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Created by Kibin to help students review key concepts, prepare for exams, and study more effectively. This Study Pack was checked for accuracy and curriculum alignment using authoritative educational sources. See sources below.

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