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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

suppose you're the economist of ethiopia; when the country is face high rate of inflation what you recommend as one economist?
Roba Reply
if consumer spend all their incomes on consumption what does it mean?
Roba
if the government spends more of its revenue on development infrastructure from the budget it have and lower tax collection the budget deficit will run why?
Roba
because tax is less than revenue
Bhat
what is demand
Sunday Reply
Demand is the quantity of goods and services that consumers are willing and able to purchase at various prices over a given period of time
adu
the total value of goods and services produced by a coutry in it's own territorial area( mainly in a year) is called GDP
fareeha Reply
GDP- the total value of goods produced and services provided in a country during one year.
fareeha
What is the formula for propensity to save
Zubair
there is no formula for propensity to save but it has a two types one is average propensity to save and marginal propensity to save where Apc is equal to saving divide by income and mpc is equal to change in saving due change in income
Bhat
yes ooo
Sunday
yes
Ahmed
okay
kawu
what is time in economics?
Sunday
what is gross domestic product
Moonga Reply
what is macroeconomics
Dickison Reply
what is macroeconomics
Majid Reply
what is macroeconomic analysis
Deogratius Reply
Macroeconomics is a branch of the economics that studies how the aggregate economy behaves. In macroeconomics, a variety of economy-wide phenomena is thoroughly examined such as inflation, price levels, rate of growth, national income, gross domestic product (GDP) and changes in unemployment Read m
wasay
Macroeconomics is a branch of the economics that studies how the aggregate economy behaves. In macroeconomics, a variety of economy-wide phenomena is thoroughly examined such as inflation, price levels, rate of growth, national income, gross domestic product (GDP) and changes in unemployment
wasay
what is wage in economics?
Sunday
what is economic
Wajeed Reply
Economics is the social science that studies the production, distribution, and consumption of goods and services. Economics focuses on the behaviour and interactions of economic agents and how economies work. 
ninad
Economics is the brench of science that deals with the study of human behavior as it related to end or scare means which have alternative used.
Jimmy
what is inflation
Junaid Reply
Inflation is simply a situation in an economy where there is a persistent rise or increase in the prices of goods and services in a particular year(say current year)
JERRY
It can still be defined as a situation in an economy where there's a persistent fall in the value of money
JERRY
it is the persistent rise in the general price of goods and services in an economy leading to the fall in the values of money
Muafue
It could mean the central bank has a deficit in reserve unable to cope with low export and exit of foreign investments.
Wong
inflation is the general increase in a commodity with in a country.
Jimmy
Mr Fallah please take the definition again that one is not clear
Muafue
the persistence in general price of commodities
ezechy
The persistence rise in the general price level
Muafue
what is willingness
Bilal Reply
Is a person Able,Capable and Anxious to something
Muafue
Is when a person is able,capable and Anxious to do something
Muafue
thanks sir g.
Bilal
u are welcome
Muafue
where you from
Bilal
Cameroon
Muafue
And you
Muafue
Pakistan
Bilal
How far are you in Education
Muafue
who about my question What is MPC
sabawoon
is marginal propensity to consume
Muafue
a little more
sabawoon
sorry muafue sir you are little bit wrong about willingness *willingness reffers how much wants . it could be wants for payment or wants for something to do.
Masadaq
MPC reffers *How much want to consume*.
Masadaq
MPC is Marginal Propensity to Consume. MPC is proportion of additional spent on consumption.
Bon
MPC is Marginal Propensity to Consume. MPC is the proportion of additional income spent on consumption.
Bon
What is difference between GNP and GDP?
Zahid
GNP is gross national product. In calculating GNP we include net national income from abroad while GDP is gross domestic product and in calculating it we use on expenditure, income and output from within the country. My name is JERRY NGONDA from Cameron
JERRY
GNP.the total value of good $service currently produce w a given period of time by domestic owner GNP=NFI+GDP:GDP is a market value of final good $service currently produce in a given period of time w in a country boundery or territors.its take produce currently $etc
tade
yes.no suggestions
tade
good Tade Feyera
Masadaq
Tade Feyera can you send me your whatsap contact number.
Masadaq
when spending by the federal government exceeds net taxes?
stefany Reply
unemployed means people are not in the labor force, who have no job, are actively looking for job, they might be return to workforce.
tiffany Reply
the number of unemployed worker out of total number of people in workforce times 100
tiffany
Explain the necessity of studying macroeconomics.
mrinmoyee Reply
how is DDP calculated
sheikh Reply
the question is not understood
Muafue
whatis GDP
tade
what is demand?
Sunday
when demand curve change
Manoj Reply
Due to unemployment rate change for example
amr
Due to external environments change
amr
Due to increase country GDP and 8ncome
amr
Due to tax rate change
amr
substitution effects government policy change in incomes
Alhassan
thanxx
Manoj
curve of demand which type?
Manoj
what is the diagram of demand curve
Manoj

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Source:  OpenStax, Macroeconomics. OpenStax CNX. Jun 16, 2014 Download for free at http://legacy.cnx.org/content/col11626/1.10
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