lecture notes: econ 203 introductory microeconomics lecture/chapter 8: the costs of taxation m. cary...
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Lecture Notes: Econ 203 Introductory MicroeconomicsLecture/Chapter 8: The costs of taxation
M. Cary LeaheyManhattan College
Fall 2012
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Goals
• This is another applications chapter looking at taxes.• This chapter reviews many of the concepts introduced in earlier
classes, particularly the tradeoff between efficiency and equity.• We introduce a new concept of dead weight loss to examine the
efficiency of a tax.
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Taxes: a brief review
• Taxes drive a wedge between prices paid by buyers and offered by sellers. Hence it distortion the market outcome.
• The tax increases the price paid and received.• The tax reduces the quantity bought and sold.• The outcome is indifferent to how the tax is levied.
• But taxes are a “cost of civilization” and are needed to fund the desired operations of government.
• But good people can differ on the kinds of taxes they want and the kinds of government spending they want.
The effects of a tax
P
Q
D
S
Revenue from tax: $T x QT
PS
PB
PE
QEQT
Size of tax = $T
The effects of a tax
Using our knowledge of welfare economics, we measure the gains and losses from a tax.
We determine: consumer surplus (CS) producer surplus (PS) tax revenue total surplus, which includes the beneficial services paid by the tax.
The effects of a tax
P
Q
D
S
Without a tax,
PE
QEQT
A
B C
D E
F
CS = A + B + C
PS = D + E + F
Tax revenue = 0
Total surplus= CS + PS= A + B + C + D + E + F
The effects of a tax
P
Q
D
S
PS
PB
QEQT
A
B C
D E
F
CS = A
PS = F
Tax revenue = B + D
Total surplus= A + B + D + F
With the tax,
The tax reduces total surplus by C + E
The effects of a tax
P
Q
D
S
PS
PB
QEQT
A
B C
D E
F
C + E is called the deadweight loss (DWL) of the tax, the fall in total surplus that results from a market distortion, such as a tax.
More on the deadweight loss
P
Q
D
S
PS
PB
QEQT
Because of the tax, the units between QT and QE are not sold.
The value of these units to buyers is greater than the cost of producing them,
so the tax prevents some mutually beneficial trades.
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Determining the deadweight loss (DWL)
• One yardstick for figuring out which goods or services to tax is to tax those with the smallest DWL, which this is the smallest distortion relative to the market outcome.
• The sixe of the DWL depends on the elasticities of supply and demand, the responsiness of supply and demand to price sold and paid.
When supply is inelastic,
it’s harder for firms to leave the market when the tax reduces PS.
So, the tax only reduces Q a little,
and DWL is small.
When supply is inelastic,
it’s harder for firms to leave the market when the tax reduces PS.
So, the tax only reduces Q a little,
and DWL is small.
DWL and the elasticity of supply
P
Q
D
S
Size of tax
DWL and the elasticity of supply
P
Q
D
S
Size of tax
The more elastic is supply,
the easier for firms to leave the market when the tax reduces PS,
the greater Q falls below the surplus-maximizing quantity,
the greater the DWL.
The more elastic is supply,
the easier for firms to leave the market when the tax reduces PS,
the greater Q falls below the surplus-maximizing quantity,
the greater the DWL.
DWL and the elasticity of demand
P
Q
D
S
Size of tax
When demand is inelastic,
it’s harder for consumers to leave the market when the tax raises PB.
So, the tax only reduces Q a little,
and DWL is small.
When demand is inelastic,
it’s harder for consumers to leave the market when the tax raises PB.
So, the tax only reduces Q a little,
and DWL is small.
DWL and the elasticity of demand
P
Q
D
S
Size of tax
The more elastic is demand,
the easier for buyers to leave the market when the tax increases PB,
the more Q falls below the surplus-maximizing quantity,
and the greater the DWL.
The more elastic is demand,
the easier for buyers to leave the market when the tax increases PB,
the more Q falls below the surplus-maximizing quantity,
and the greater the DWL.
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DWL and the elasticity of demand
P
Q
D
S
Size of tax
The more elastic is demand,
the easier for buyers to leave the market when the tax increases PB,
the more Q falls below the surplus-maximizing quantity,
and the greater the DWL.
The more elastic is demand,
the easier for buyers to leave the market when the tax increases PB,
the more Q falls below the surplus-maximizing quantity,
and the greater the DWL.
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The proper size of government: discussion
Class discussion. How to fund the needed operations of government-defense, highways etc.
What should be taxed: groceries or restaurant meals?
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The proper size of government
Bigger government means more services but requires higher taxes and higher DWLs.
The larger the DWLs, the greater the argument for smaller govt.
With labor income taxes the largest single revenue source, the elasticity of labor supply depends the size of the DWL
If labor supply is elastic, then the DWL is large.
If labor supply is inelastic, then the DWL is small.
Size of the elasticity is not just an empirical question but a question of morality to some.
Reasons for high elasticity:
Many workers can adjust hours/are second earners/elderly and don’t “need” the income/work underground
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Q2 Q1
DWL and the size of the tax
P
Q
D
S
causes the DWL to more than double.
Doubling the tax
2T T
Initially, the tax is T per unit.
initial DWL
new DWL
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1919
Q3
DWL and the size of the tax
P
Q
D
S
Q1
3T Tcauses the DWL to more than triple.
Tripling the tax
Initially, the tax is T per unit.
initial DWL
new DWL
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2020
DWL and the size of the tax
DWL
Tax size
Summary
When a tax increases, DWL rises even more.
Implication
When tax rates are low, raising them doesn’t cause much harm, and lowering them doesn’t bring much benefit.
When tax rates are high, raising them is very harmful, and cutting them is very beneficial.
Implication
When tax rates are low, raising them doesn’t cause much harm, and lowering them doesn’t bring much benefit.
When tax rates are high, raising them is very harmful, and cutting them is very beneficial.
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2121
Q2
DWL and the size of the tax
P
Q
D
S
Q1
PB
PS
PB
PS
2T T
When the tax is small, increasing it causes tax revenue to rise.
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2222
Q3
DWL and the size of the tax
P
Q
D
S
Q2
PB
PS
PB
PS
3T 2TWhen the tax is larger, increasing it causes tax revenue to fall.
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The Laffer curve shows the relationship between the size of the tax and tax revenue.
DWL and the size of the tax: an extreme example
Tax size
Tax revenue
The Laffer curve
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Summary
Taxes reduce the welfare of buyers and sellers. This welfare loss usually exceeds the revenue gain.
The decline in total surplus (consumer surplus and producer surplus and tax revenue) is called the deadweight loss of the tax.
Taxes have deadweight losses because they causes consumer to buy less and seller to sell less, thus shrinking the market.
The size of the DWLs depend on the elasticities of supply and demand. Higher elasticizes imply higher DMLs.
DWLs increases even more than the size of the tax.
In one extreme case, revenue may actually fall as taxes become too large. But this rarely happens in real life.