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Aggregate Demand and Aggregate Supply
Lecture 12
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Aggregate Demand |
Aggregate Demand –
schedule that shows how much goods and services people want to buy
for a price level
Price
level – price index for all goods and services
GDP – total
value of all goods and services produced in an economy in one year
Not a market
demand function!
Negative Slope
Real Balance
Effect
An increasing
price level is inflation
A decreasing
price level is deflation
As the price
level increases, inflation reduces the value of money, saving,
and investments
People buy
less goods and services
Lower wealth
Interest Rate
Effect – ignore
Foreign Purchase
Effect – how one country’s price level compares to another
If the U.S.
price level is higher to another country
U.S. imports
more
U.S. exports
less
Exchange rate
did not change
AD Shifts
Economy has four
sectors that buy goods and services
GDP = C + I + G
+NX
C is consumers
I is business
investment
G is government
spending
NX is net
exports
Trick – does
it increase spending or decrease spending?
Consumers
Consumer
spending
Real wealth
Household debt
Consumer
expectations
Taxes
Business
investment
Interest rates
Expected
profits
Technology
Taxes
Production
capacity
Gov. spending
International
sector
Net exports
Exchange rates
Foreign income
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Aggregate
Supply |
Aggregate Supply –
schedule that shows amount of goods and services producers will
supply
Short run –
some resource prices do not change immediately to changes in price
level
Resource prices : Manufacturing
: Product prices
Long run – all
resource prices change immediately to changes in the resource price
Short-run
aggregate supply
-
Has positive
slope
Why?
If price level
increases, then producers produce more, thus GDP increases
Workers real
wages decrease, so workers are “fooled” into producing more
for a lower real wage
Change “fooled”
into “exploited”
Long-run
Aggregate Supply
-
All resource
prices increase with the price level
Keynes – “In
the long run, we are all dead!”
Thus, nominal
prices are irrelevant for the long run
Note –
hyperinflation causes society to breakdown, thus GDP decreases;
problems with the AD-AS graph
Shifting the AS
curve
Trick – does
it increase or decrease business cost or resource prices?
Labor –
immigration; causes wages to decrease
Capital –
buildings, machines, and equipment
Materials
Productivity –
workers produce more given the same output
Market power
OPEC – higher
energy prices cause AS to shift left
Legal Structure
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Equilibrium |
A price shock
causes the price level to increase to P”
Price level is
too high
Producers
produce too much and consumers buy too little
Business
inventories increase
Producers reduce
production until economy is at GDPFE again
A price shock
causes the price level to decrease to P’
Price level is
too low; consumers want to buy more than what is available
Business
inventories are falling
Producers
increase production
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Examples |
Government allows
immigrants into the country
Wages fall; thus
decreasing business costs
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GDP may increase
to Q1 or Q2, depending on the price level
Price level is
ambiguous
If prices are
flexible, then the price level falls and output increases to Q1
If prices are
“sticky” downward, then price level does not decrease and GDP
increases to Q2
Sticky prices
may causes GDP to swing more than if prices were flexible
Why prices do not
decrease?
Companies do not
want to start a price war
Menu costs –
company has to change prices in inventories, catalogues, etc.
Wage contracts –
workers are “locked” into wage contracts
Unions
Minimum wage
laws reflect a workers’ level of productivity
If a business
lowered wages, then workers’ morale and work habits decrease
Workers lower
production
Lower wages
creates bitter feelings
Employees may
steal more
Sabotage –
plant a virus into a computer system
Espionage –
post trade secrets on the internet or send it to competitors
OPEC causes a
price shock by increasing the price of oil
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Petroleum is
used in many manufacturing products, fertilizers, plastics, and
transportation fuels
Thus, business
costs increase, causing the AS curve to shift leftward
The GDP falls,
causing a recession
The price level
increases, creating inflation
Cost push
inflation – the worst kind; the economy has inflation and a
recession (i.e. higher unemployment).
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