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By the end of this section, you will be able to:
  • Explain how productivity growth changes the aggregate supply curve
  • Explain how changes in input prices changes the aggregate supply curve

The original equilibrium in the AD/AS diagram will shift to a new equilibrium if the AS or AD curve shifts. When the aggregate supply curve shifts to the right, then at every price level, a greater quantity of real GDP is produced. When the SRAS curve shifts to the left, then at every price level, a lower quantity of real GDP is produced. This module discusses two of the most important factors that can lead to shifts in the AS curve: productivity growth and input prices.

How productivity growth shifts the as curve

In the long run, the most important factor shifting the AS curve is productivity growth . Productivity means how much output can be produced with a given quantity of labor. One measure of this is output per worker or GDP per capita    . Over time, productivity grows so that the same quantity of labor can produce more output. Historically, the real growth in GDP per capita in an advanced economy like the United States has averaged about 2% to 3% per year, but productivity growth has been faster during certain extended periods like the 1960s and the late 1990s through the early 2000s, or slower during periods like the 1970s. A higher level of productivity shifts the AS curve to the right, because with improved productivity, firms can produce a greater quantity of output at every price level. [link] (a) shows an outward shift in productivity over two time periods. The AS curve shifts out from SRAS 0 to SRAS 1 to SRAS 2 , reflecting the rise in potential GDP in this economy, and the equilibrium shifts from E 0 to E 1 to E 2 .

Shifts in aggregate supply

The two graphs show how aggregate supply can shift and how these shifts affect points of equilibrium. The graph on the left shows how productivity increases will shift aggregate supply to the right. The graph on the right shows how higher prices for key inputs will shift aggregate supply to the left.
(a) The rise in productivity causes the SRAS curve to shift to the right. The original equilibrium E 0 is at the intersection of AD and SRAS 0 . When SRAS shifts right, then the new equilibrium E 1 is at the intersection of AD and SRAS 1 , and then yet another equilibrium, E 2 , is at the intersection of AD and SRAS 2 . Shifts in SRAS to the right, lead to a greater level of output and to downward pressure on the price level. (b) A higher price for inputs means that at any given price level for outputs, a lower quantity will be produced so aggregate supply will shift to the left from SRAS 0 to AS 1 . The new equilibrium, E 1 , has a reduced quantity of output and a higher price level than the original equilibrium (E 0 ).

A shift in the SRAS curve to the right will result in a greater real GDP and downward pressure on the price level, if aggregate demand remains unchanged. However, if this shift in SRAS results from gains in productivity growth, which are typically measured in terms of a few percentage points per year, the effect will be relatively small over a few months or even a couple of years.

How changes in input prices shift the as curve

Higher prices for inputs that are widely used across the entire economy can have a macroeconomic impact on aggregate supply. Examples of such widely used inputs include wages and energy products. Increases in the price of such inputs will cause the SRAS curve to shift to the left, which means that at each given price level for outputs, a higher price for inputs will discourage production because it will reduce the possibilities for earning profits. [link] (b) shows the aggregate supply curve shifting to the left, from SRAS 0 to SRAS 1 , causing the equilibrium to move from E 0 to E 1 . The movement from the original equilibrium of E 0 to the new equilibrium of E 1 will bring a nasty set of effects: reduced GDP or recession, higher unemployment because the economy is now further away from potential GDP, and an inflationary higher price level as well. For example, the U.S. economy experienced recessions in 1974–1975, 1980–1982, 1990–91, 2001, and 2007–2009 that were each preceded or accompanied by a rise in the key input of oil prices. In the 1970s, this pattern of a shift to the left in SRAS leading to a stagnant economy with high unemployment and inflation was nicknamed stagflation    .

Conversely, a decline in the price of a key input like oil will shift the SRAS curve to the right, providing an incentive for more to be produced at every given price level for outputs. From 1985 to 1986, for example, the average price of crude oil fell by almost half, from $24 a barrel to $12 a barrel. Similarly, from 1997 to 1998, the price of a barrel of crude oil dropped from $17 per barrel to $11 per barrel. In both cases, the plummeting price of oil led to a situation like that presented earlier in [link] (a), where the outward shift of SRAS to the right allowed the economy to expand, unemployment to fall, and inflation to decline.

Along with energy prices, two other key inputs that may shift the SRAS curve are the cost of labor, or wages, and the cost of imported goods that are used as inputs for other products. In these cases as well, the lesson is that lower prices for inputs cause SRAS to shift to the right, while higher prices cause it to shift back to the left.

Other supply shocks

The aggregate supply curve can also shift due to shocks to input goods or labor. For example, an unexpected early freeze could destroy a large number of agricultural crops, a shock that would shift the AS curve to the left since there would be fewer agricultural products available at any given price.

Similarly, shocks to the labor market can affect aggregate supply. An extreme example might be an overseas war that required a large number of workers to cease their ordinary production in order to go fight for their country. In this case, aggregate supply would shift to the left because there would be fewer workers available to produce goods at any given price.

Key concepts and summary

The aggregate demand/aggregate supply (AD/AS) diagram shows how AD and AS interact. The intersection of the AD and AS curves shows the equilibrium output and price level in the economy. Movements of either AS or AD will result in a different equilibrium output and price level. The aggregate supply curve will shift out to the right as productivity increases. It will shift back to the left as the price of key inputs rises, and will shift out to the right if the price of key inputs falls. If the AS curve shifts back to the left, the combination of lower output, higher unemployment, and higher inflation, called stagflation, occurs. If AS shifts out to the right, a combination of lower inflation, higher output, and lower unemployment is possible.

Questions & Answers

What is an indifference curve?
layla Reply
different levels of utilities of a person in a given set of bundles of goods
identify and quantify five social costs and social benefits of building a school
Mokgobo Reply
identify and quantity five social costs and social benefits of building a hospital
short run vs long run
state the law of diminishing return?
The Law of Diminishing (Marginal) Returns simply states that at some point in time a business/operation/etc.'s increased productivity will begin to decline.
For example, if a small pizza shop currently has 3 workers in the kitchen at any given time,and hiring 1 more worker will increase productivity, at some number of workers hired will the business see a decrease in productivity because the capital resources that the pizza shop has is not infinite.
Five social benefits of building a hospital, in my opinion and depending on where it's built, would be 1) Increased care for neighboring residents, 2) Potential jobs for individuals, 3) May decrease the travel time residents need to endure in order to reach the nearest hospital
4) May create work-study programs for individuals who aspire to be future Doctors, Nurses, Physicians, etc. 5) Assuming there are local pharmaceutical businesses nearby, the hospital may decide to purchase supplies local, increasing the business' sales. Thus, generating more income.
5 costs of building a hospital would be 1) Increased noise and waste pollution from service vehicles and hospital visitors, 2) May require large amounts of space, possibly jeopardizing nearby animal habitats, 3) May see an increase in traffic and possibly car accidents from frantic individuals
racing to see their injured friends, family members, etc. 4) Constructing a hospital and hiring staff is very expensive 5) To use funds, private or public, to finance the construction of a hospital cannot be used to fund any other projects. (The concept of opportunity costs.)
what is meant by inteference with the price mechanism operation?
is it true that the opportunity cost of unemployed labour is zero?
Wisdom Reply
give two forms of collusion
nondumiso Reply
1.Explicit Collusion: Also termed overt collusion, this occurs when two or more firms in the same industry formally agree to control the market .
2.Implicit Collusion: Also termed tacit collusion, this occurs when two or more firms in the same industry informally agree to control the market, often through nothing more than interdependent actions. A prime example of implicit collusion is price leadership .
explicit collusion: this occurs when two or more firms in the same industry legally agree to control the market
implicit collusion this occurs when two or more firms in the same industry illegally agree to control the market
what is responsible for investigating cases of collusion
reasons why a country maybe involved in international trade
Nde Reply
state five similarities and differences between money market and capital market
Victoria Reply
Give a Zimbabwean example of firms operating in an oligopoly market and illustrate using diagrams how a manager in such a market maximize profit
Pam Reply
what is an industry
EWAH Reply
An industry is the production of goods and related services within an economy
an industry is place where goods and services are produced for human consumption....
scarcity is the major course of economics problems. discuss
Abdulhameed Reply
please say about that it is interesting for us
what is economics
Michael Reply
economics is a social sciences that deals with the production distribution and consumption of goods and services produced.its study of behaviour between economic agents
what is the formula for elasticity of demand
change in demand/change in variable variable may be price, income,
seasonal unemployment
Enoch Reply
example agriculture
want and scarcity
why the average of revenue AR fun
What is monopoli
Gadrey Reply
What is monopoly
monipoly ..where one firm controls all the market
what is demand
Jafar Reply
demand is what one willing and enable to purchase at a given price over period of a time.
what is marginal revenue
distinguish between commercialization and industrialization
Alhassan Reply
why division of labour increase economy level of production
Henry Reply

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Source:  OpenStax, Principles of economics. OpenStax CNX. Sep 19, 2014 Download for free at http://legacy.cnx.org/content/col11613/1.11
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