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Dead weight loss and Tax
Presented by-☺ Pooja goyal 13189☺ Pooja sharma 13190☺ Priyanka meena 13210☺ Pia singh 13186
Dead weight loss occurs when government imposes tax on commodity, and both producer and consumer loose part of their surplus, the loss suffers by both producer and consumer is dead weight loss.
TAX
Tax WedgeA tax places a wedge between
the price buyers pay and the price sellers receive.
Because of this tax wedge, the quantity sold falls below the level that would be sold without a tax.
The size of the market for that good shrinks.
Tax Revenue
Copyright © 2004 South-Western
Taxrevenue
(T × Q)
Size of tax (T)
Quantitysold (Q)
Quantity0
Price
Demand
Supply
Quantitywithout tax
Quantitywith tax
Price buyers
pay
Price sellersreceive
How a Tax Effects Welfare
Copyright © 2004 South-Western
A
F
B
D
C
E
Quantity0
Price
Demand
Supply
=PB
Q2
=PS
Pricebuyerspay
Pricesellersreceive
=P1
Q1
Pricewithout tax
Determinants of Deadweight Loss
What determines whether the deadweight loss from a tax is large or small? The magnitude of the deadweight
loss depends on how much the quantity supplied and quantity demanded respond to changes in the price.
That, in turn, depends on the price elasticities of supply and demand.
Determinants of Deadweight LossThe greater the elasticities of
demand and supply:◦ the larger will be the decline in
equilibrium quantity and,◦ the greater the deadweight loss of a
tax.
Tax Distortions and Elasticities
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(a) Inelastic Supply
Price
0 Quantity
Demand
Supply
Size of tax
When supply isrelatively inelastic,the deadweight lossof a tax is small.
Tax Distortions and Elasticities
Copyright © 2004 South-Western
(b) Elastic Supply
Price
0 Quantity
Demand
SupplySizeoftax
When supply is relativelyelastic, the deadweightloss of a tax is large.
Tax Distortions and Elasticities
Copyright © 2004 South-Western
Demand
Supply
(c) Inelastic Demand
Price
0 Quantity
Size of taxWhen demand isrelatively inelastic,the deadweight lossof a tax is small.
Tax Distortions and Elasticities
Copyright © 2004 South-Western
(d) Elastic Demand
Price
0 Quantity
Sizeoftax Demand
Supply
When demand is relativelyelastic, the deadweightloss of a tax is large.
Extreme casesIf demand were perfectly inelastic (a
vertical demand curve), the quantity demanded is unchanged by the imposition of the tax. As a result, the tax imposes no deadweight loss.
Similarly, if supply were perfectly inelastic (a vertical supply curve), the quantity supplied is unchanged by the tax and there is also no deadweight loss.
Deadweight Loss and Tax Rate
With each increase in the tax rate, the deadweight loss of the tax rises even more rapidly than the size of the tax.
Tax Revenue and Tax RateFor the small tax, tax revenue is
small.As the size of the tax rises, tax
revenue grows.But as the size of the tax
continues to rise, tax revenue falls because the higher tax reduces the size of the market.
Deadweight Loss and Tax Revenue from Three Taxes of Different Sizes
Copyright © 2004 South-Western
Tax revenue
Demand
Supply
Quantity0
Price
Q1
(a) Small Tax
Deadweightloss
PB
Q2
PS
Deadweight Loss and Tax Revenue from Three Taxes of Different Sizes
Copyright © 2004 South-Western
Tax revenue
Quantity0
Price(b) Medium Tax
PB
Q2
PS
Supply
Demand
Q1
Deadweightloss
Deadweight Loss and Tax Revenue from Three Taxes of Different Sizes
Copyright © 2004 South-Western
Tax
reve
nue
Demand
Supply
Quantity0
Price
Q1
(c) Large Tax
PB
Q2
PS
Deadweightloss
How Deadweight Loss and Tax Revenue Vary with the Size of a Tax
Copyright © 2004 South-Western
DeadweightLoss
0 Tax Size
How Deadweight Loss and Tax Revenue Vary with the Size of a Tax – Laffer curve
Copyright © 2004 South-Western
TaxRevenue
0 Tax Size
Laffer Curve The Laffer curve depicts the
relationship between tax rates and tax revenue.
Supply-side economics : refers to the views of Reagan and Laffer who proposed that a tax cut would induce more people to work and thereby have the potential to increase tax revenues.
IN MONOPOLY
The Deadweight LossIn monopoly, firm sets its price
above marginal cost, it places a wedge between the consumer’s willingness to pay and the producer’s cost.◦This wedge causes the quantity sold
to fall short of the social optimum.
The Inefficiency of Monopoly
Quantity0
PriceDeadweight
loss
DemandMarginalrevenue
Marginal cost
Efficientquantity
Monopolyprice
Monopolyquantity
The Deadweight LossThe deadweight loss caused by a
monopoly is similar to the deadweight loss caused by a tax.
The difference between the two cases is that the government gets the revenue from a tax, whereas a private firm gets the monopoly profit.
For reducing deadweight loss, in monopoly, price discrimination is use.
PRICE DISCRIMINATIONPrice discrimination is the
business practice of selling the same good at different prices to different customers, even though the costs for producing for the two customers are the same.
PRICE DISCRIMINATIONPrice discrimination is not possible when
a good is sold in a competitive market since there are many firms all selling at the market price. In order to price discriminate, the firm must have some market power.
Perfect Price Discrimination◦Perfect price discrimination refers to the
situation when the monopolist knows exactly the willingness to pay of each customer and can charge each customer a different price.
PRICE DISCRIMINATIONTwo important effects of price
discrimination:◦It can increase the monopolist’s
profits.◦It can reduce deadweight loss.
Welfare with and without Price Discrimination
Copyright © 2004 South-Western
Profit
(a) Monopolist with Single Price
Price
0 Quantity
Deadweightloss
DemandMarginalrevenue
Consumersurplus
Quantity sold
Monopolyprice
Marginal cost
Welfare with and without Price Discrimination
Profit
(b) Monopolist with Perfect Price Discrimination
Price
0 Quantity
Demand
Marginal cost
Quantity sold
Estimating Dead Weight Loss Due to Imperfectly Competitive Market Structures
Economists are naturally interested in estimating the size of dead weight losses (DWLs) resulting from allocative inefficiency. Estimating DWL is difficult because the investigator will not normally know the true value of marginal cost. Hence, DWL must be estimated indirectly.
Harburger’s ApproachThe ABH dead weight triangle is approximated by the following equation (equation 4.1 in the text):
))((21
MCCM QQPPDWL
By algebraic manipulation it can be shown that:
**21 2 QPdDWL [1]
Explanation of equation is price elasticity of demand
d is the price cost margin, that is:
PMCPd
P* is the monopoly price
Q* is the monopoly output
•To estimate d, Harburger measured the difference between rate of return for the industry and the average rate of return for all industries. •Harburger assumed that, for all industries, = 1
Harburger’s estimates
Based on data for U.S. industries in the 1920s, Harburger estimated the DWL due to monopoly to be equal to 1/10 of 1 percent of GNP. Hence, the welfare loss due to pricing above marginal cost is very small and would hardly justify the allocation of substantial resources for antitrust enforcement.
Cowling and Mueller’s Approach
above reveals that estimates of DWL are sensitive to assumptions made about elasticity of demand ( )Cowling and Mueller made adjustments to the methodology used by Harburger and , using a sample of 734 U.S. firms for 1963-66, reached radically different conclusions as regards the magnitude of welfare losses.•Cowling and Mueller changed a key assumption of Harburger; namely, that for all industries, = 1.
To estimate industry-level price elasticities (), Cowling and Mueller took advantage of the fact that the firm’s profit maximizing price (P*) satisfies the following condition:
MCPP
** [2]
Recall that d is the price-cost margin . Thus we can say:
MCPP
d
**1 [3]
Thus by equation [2], we can say:
d1 Thus if you
can estimate d, you can estimate
Thus substitute 1/d for in equation [1] and you get:
**21**1
21 2 QdPQPd
dDWL
[4]
Substituting (P*- MC)/P* for d in equation [4] gives us:
*21*)*(
21***
21
QMCPQPP
MCPDWL [5]
Thus, Cowling and Mueller showed that DWL for an industry was equal to ½ of the economic profits () of firms in the industry.
Pric
e
Quantity0
PM
QM
MC
DMR
PC
QC
A
B
C
Figure 1
Pric
e
Quantity0
P*
Q*
MC
DMR
*21*)*(
21***
21
QMCPQPP
MCPDWL
•DWL is given by the black –shaded triangle.• is given by the green-shaded rectangle
Measuring Dead Weight Loss
Cowling and Mueller’s resultsAssuming that 12 percent is a "normal" rate of return on capital, Cowling and Mueller produced 2 estimates of DWL in the U.S. economy:• The low estimate, which does not include advertising expenditures as a component of the dead weight loss, was 4 percent of GNP (about $403 billion in 2001). • The high estimate, which reckoned advertising expenditures as "wasted resources," was 13 percent of GNP (about $1.394 trillion in 2001).