<< Chapter < Page Chapter >> Page >
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

factor affecting or influencing changes in supply
Sham Reply
What is economics
Khurram Reply
we study how to allocate scare resouces to satisfied unlimited wants.
Adil
Scenario affecting change in income in demand
Janiz Reply
what economic
guuguule Reply
it is the situation where by im a market there is only one supplier and producer of a certain comodity that has no close substitute or competitor
Sepiso Reply
yes
Alhaji
what is demand and supply
Alhaji
demand is the amount of a goods or service that consumers are willing to buy at a particular price, while is to provide something,to make something available for use.
jago
I need a scenario affecting change in income (demand)
Janiz
what is Economics?
Pintu Reply
Is the study of human behaviour as a relationship between ends and scares mean which have alternative use
Alhaji
yes
Tawa
what is monopoly
Alhaji
what are the difficultés if retail prix index for calculating thé value of money
Oscar
hmm OK wait
Castino
what is labour
Mamudou Reply
LABOUR is a measure of work done by human being
Blessing
It is all form of human effort use to utilize in production
Alhaji
Why is scarcity a foundermental problem in economics
Alhaji
Why is scarcity a foundermental problem in economics
Alhaji Reply
scarcity occur unbalance demand and supply at this time cost goods increase then inflation very increase
Tesfaye
scarcity is a foundermental problem because its a natural situation and it affects the world at Large.in other words,it's limit in supply relating to deman
Akwosih
'Economics is about making choices in the presence of scarcity"
manoj Reply
. 'Economics is about making choices in the presence of scarcity" - Dscuss.
manoj
describe the producer's scarce resources.. I.e land,Labour,capital and enterprise
Alfhah Reply
short in supply
Charles
What are human behaviour?
Regina Reply
the rationality in decision making
Charles
how can you describe economic goods in a much better easier way?
Alfhah Reply
any thing that have utility
Charles
what is deman and supply
Aruna Reply
Demand can be defined as the ability and willingness to buy commodities in a given price of goods and services in a particular period of time
Alasana
supply refers to the ability and willingness to offered commodities for sale in a given price of goods and services in a period of time .
Alasana
Demand can refer to the ability and willingness to purchase a commodity at a giving price and time.
habib
what must the producer do if total costs exceed total revenue
Mmusi Reply
raise price
Nguyen
reduce cost
Charles
scarcity resources sample
nawala Reply
land
Charles

Get the best Principles of economics course in your pocket!





Source:  OpenStax, Principles of economics. OpenStax CNX. Sep 19, 2014 Download for free at http://legacy.cnx.org/content/col11613/1.11
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Principles of economics' conversation and receive update notifications?

Ask