AE equilibrium At full employment, real GDP equals potential GDP and the unemployment rate equals the natural unemployment. Y = Y FE u c = 0 g ≈ 3% ≈ 2% u ≈ 5% Potential GDP and the natural unemployment rate are determined by real factors and are independent of the PL. Changes in the quantity of money change nominal GDP and the PL but have no effect on potential GDP. Aggregate Demand (AD) is derived from Snarrian aggregate expenditure by imposing the AE equilibrium (Y = AE ) and then solving for PL. AE = [W + Y e – PL – r – mpc ∙ T + I + G + X ] + { mpc – mpm }Y AD is the relationship between the quantity of real GDP demanded and the price level when all other influences on expenditure plans remain the same AD and Aggregate Supply (AS) determine equilibrium real GDP and the PL AD-AS-FE Model
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AE equilibrium At full employment, real GDP equals potential GDP and the unemployment rate equals the natural unemployment. Y = Y FE u c = 0 g 3% 2% u.
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AE equilibrium At full employment, real GDP equals potential GDP and the unemployment rate
equals the natural unemployment.
Y = YFE uc = 0 g ≈ 3% ≈ 2% u ≈ 5%
Potential GDP and the natural unemployment rate are determined by real factors and are independent of the PL.
Changes in the quantity of money change nominal GDP and the PL but have no effect on potential GDP.
Aggregate Demand (AD) is derived from Snarrian aggregate expenditure by imposing the AE equilibrium (Y = AE ) and then solving for PL.
AE = [W + Ye – PL – r – mpc ∙ T + I + G + X ] + { mpc – mpm }Y
AD is the relationship between the quantity of real GDP demanded and the price level when all other influences on expenditure plans remain the same
AD and Aggregate Supply (AS) determine equilibrium real GDP and the PL
AD-AS-FE Model
“Snarrian” Aggregate Demand is found by substituting
AE = [W + Ye – PL – r – mpc ∙ T + I + G + X ] + { mpc – mpm }Y
Y = [W + Ye – PL – r – mpc ∙ T + I + G + X ] + { mpc – mpm }Y
PL = [W + Ye – r – mpc ∙ T + I + G + X ] + { mpc – mpm }Y – 1 Y
PL = [W + Ye – r – mpc ∙ T + I + G + X ] + { mpc – mpm – 1 }Y
PL = [W + Ye – r – mpc ∙ T + I + G + X ] – {– mpc + mpm + 1 }Y
PL = [W + Ye – r – mpc ∙ T + I + G + X ] – {1 – mpc + mpm }Y
PL = [W + Ye – r – mpc ∙ T + I + G + X ] – {mps + mpm }Y
Aggregate Demand
Marginal propensity to
save
Marginal propensity to
save
Snarrian Aggregate Demand
Example: In our continuing numerical example of the economy, W = 5, Ye = 7, PL = 8, r = 2, T = 3, I = 1, G = 3.5, X = 0.5 with mpc = 0.75, and mpm = 0.25. Derive the AD equation.
First, ignore the fact that PL = 8 because AD isthe relationship between real GDP and PL.
PL = [W + Ye – r – mpc ∙ T + I + G + X ] – {mps + mpm }Y
AD’ Note: Cutting T raises the $500 billion budget
deficit to $1 trillion
Aggregate Demand
Excel Simulation Assignment 4
Aggregate Demand
PL = [W + Ye – r – mpc ∙ T + I + G + X ] – { mps + mpm }∙ Y
AD increases if W, Ye, I, G or X increase OR if r or T decrease
AD decreases if W, Ye, I, G or X decrease OR if r or T increase
The Congress and President are in charge of fiscal policy. Expansionary fiscal policy involves a cut in T and/or increase in G Restrictive fiscal policy involves a raising T and/or cutting G
The Federal Reserve (our central bank) is in charge of monetary policy Expansionary monetary policy involves lowering the federal funds interest rate Restrictive monetary policy involves raising the federal funds interest rate
Aggregate Demand
Potential GDP is determined by the quantities of Labor employed Capital, human capital, and the state of technology Land and natural resources Entrepreneurial talent
At full employment (Y = YFE, g ≈ 3%, ≈ 2%, uc = 0, u ≈ 5%),
The real wage rate makes the quantity of labor demanded equal to the quantity of labor supplied.
Along the potential GDP line, when the price level changes the money wage rate changes to keep the real wage rate at the full-employment level.
Since u equals the natural rate of unemployment there is no pressure on inflation to change
Over the business cycle The quantity of labor employed fluctuates around its full employment level. Real GDP fluctuates around potential GDP
Potential GDP
Full-employment
Example: Suppose the economy’s production function shows the volume of output that can be produced by its labor force of size L given levels of K units of capital, R units of resources and z percent of the knowledge/talent that is contained in the universe.
Suppose there are a total of L = 144 (million) workers in the economy with resources, capital, and technology/talent currently at R = 400 (million acres of land and barrels of oil), K = 100 (million machines/roads/networks) and z = 1 (percent).
1. What is the economy’s short-run production function? Graph it.
0.005 1 100 400Y L
0.005Y z K R L
Potential GDP
0.005 40,000Y L
0.005 200Y L
Y L
Short-run production function
0
2
4
6
8
10
12
14
0 25 50 75 100 125 150 175
labor
real
GD
P
Short-run production function
0
2
4
6
8
10
12
14
0 25 50 75 100 125 150 175
labor
real
GD
P
Short-run production function
0
2
4
6
8
10
12
14
0 25 50 75 100 125 150 175
labor
real
GD
P
Short-run production function
0
2
4
6
8
10
12
14
0 25 50 75 100 125 150 175
labor
real
GD
P
Short-run production function
0
2
4
6
8
10
12
14
0 25 50 75 100 125 150 175
labor
real
GD
P
Full-employment
Example (continued):
2. Graph the economy’s short-run production function:
Y L
Potential GDP
L Y
0 0.00
50 7.07
100 10.00
150 12.25
Short-run production function
0
2
4
6
8
10
12
14
0 25 50 75 100 125 150 175
labor
real
GD
P
er
Short-run production function
0
2
4
6
8
10
12
14
0 25 50 75 100 125 150 175
labor
real
GD
P
Full-employment
Example (continued):
3. Compute potential GDP.
Y L
YFE = 12 (trillion $)
Potential GDP
144Y
12
144er
Full-employment
Example (continued):
4. Compute the output of the economy if only 121 million of the 144 million in the labor force are working.
23 million workers
are (cyclically)
unemployed, resulting
in Y < YFE
Potential GDP
Y L
Y = 11 (trillion $)
121Y
Short-run production function
0
2
4
6
8
10
12
14
0 25 50 75 100 125 150 175
labor
real
GD
P
144121
11
er
Full-employment
Example (continued):
5. Compute the output of the economy if all 144 million workers in the labor force are full time (40 hours per week) and 50 million of them are working 20 hours of overtime per week.
Potential GDP
Short-run production function
0
2
4
6
8
10
12
14
0 25 50 75 100 125 150 175
labor
real
GD
P
144
Since Y > YFE the unemployment rate is
‘low’
Since 50 million are working an extra 20
hours/wk, the effective size of the (fulltime)
work force is
L = 144 + 50/2 = 169
169 13Y
13
er
Short-run production function
0
2
4
6
8
10
12
14
0 25 50 75 100 125 150 175
labor
real
GD
P
Short-run production function
0
2
4
6
8
10
12
14
0 25 50 75 100 125 150 175
labor
real
GD
P
Full-employment
Example (continued):
6. Compute potential GDP if capital increases to K = 121 (million machines/roads/networks). What is the new level of potential GDP?
Potential GDP
144
0.005 1 400 100Y L
0.005 48,400Y L
0.005 220Y L
1.1Y = L
121
YFE = 13.2 (trillion $)
1.1 144Y
13.2
er
Potential GDP
Full-employment
Example (continued):
7. Increases in an economy’s resources and knowledge/talent have the same effect as an increase in capital.
8. Graph the potential GDP you computed in part (3) with AD below.
Y
PL YFE
0
12.75
12
AD
Together, AS and AD determine equilibrium real GDP and the PL
The goal of policy makers is to keep
equilibrium real GDP “close” to potential
GDP with
g ≈ 3% ≈ 2%u ≈ 5%
Aggregate Supply is the relationship between the quantity of real GDP supplied and PLwhen all other influences on production plans remain the same The AS curve is positively sloped (AS slope = )
Firms maximize profits. If prices increase while all other costs are constant, production rises because it is more profitable. Firm supply, industry supply and AS slope up.
Alternatively, when PL rises with constant wages, real wages falls, employment rises, and quantity of real GDP supplied rises.
Shifters of AS are contained in its intercept: The money wage rate changes (w). The money prices of other resources change (p). Government changes supply-side taxes () Potential GDP changes:
Advances in technology (z) Increases in the size of the Labor Force (L) Increased public or private investment in capital (K) Increased Land and natural resources (R)
The general form of AS:
PL = [w + p + – z – K – R – L ] + ∙ YAS
Along the AS curve, the only influence on production plans that changes is PL. That is, the quantity of real GDP supplied increases (decreases) when the PL rises (falls).
Aggregate Supply
Snarrian Aggregate Supply
Example: Suppose money wage rate is $400 per week (w = 400) and money prices of other resources of $230 per week (p = 230) given a supply-side tax rate of 15.75 percent (), technological advancement of 1 percent (z = 1), accumulated capital of 100 million machines/roads/networks (K = 100), 400 million acres of land and barrels of oil (R = 400), and a labor force of 144 million workers (L = 144). 1. Derive the AS equation which has a slope of = 0.5.
4. Graph potential GDP (YFE = 12) with AS equation found in part (1).
PL = 0.75 + 0.5 Y
If real GDP equals YFE, the PL = 6.75
If the PL is greater than 6.75, real GDP
exceeds potential GDP.
If the PL < 6.75, real GDP is less than potential GDP
YFE
12
0.75
Y
PL
6.75
AS
ASAS
YFE
13.5
YFE
Snarrian AS
Example (continued):
5. Show what happens to AS and YFE when technology increases.
PL = [w + p + – z – K – R – L ] + ∙ YAS
Potential GDP immediately shifts to
the right
The increases in z decrease the value of
the AS intercept.
AS increases(shifts to the right)
12 Y
PL
6.75
Aggregate Supply
Snarrian AS
Example (continued):
6. Graph AS with potential GDP and AD below.
AD
PL = 0.75 + 0.5 Y
PL = 0.75 + 0.5 (12) = 6.75
Together, AS and AD determine equilibrium real
GDP and the PL
The goal of policy makers is to keep equilibrium real
GDP “close” to potential GDP with
g ≈ 3% ≈ 2%u ≈ 5%
Aggregate Supply
YFE
12 Y
PL
6.75
AS
0.75
Aggregate Supply
PL = [w + p + – z – K – R – L ] + ∙ YAS
AS decreases if w, p, or increase OR if z, K, R or L decrease
AS increases if w, p, or decrease OR if z, K , R or L increase
The Congress and President are in charge of fiscal policy. Expansionary supply-side fiscal policy involves cutting Restrictive supply-side fiscal policy involves raising
The Federal Reserve (our central bank) is in charge of monetary policy Expansionary monetary policy lowers the federal funds interest rate Restrictive monetary policy raises the federal funds interest rate
Aggregate Supply
Inflationary gaps
Example: Suppose potential GDP is $11 trillion and AS and AD are given by