1. Topic 8 ： Taxation(1)- Positive Principles of Taxation

2. Taxes The government levies taxes on many goods & services to raise revenue to pay for national defense, public schools, etc. The government can make buyers or sellers pay the tax. The tax can be a percentage of the good ’ s price, or a specific amount for each unit sold. –For simplicity, we analyze per-unit taxes only.

3. S1S1 EXAMPLE : The Market for Pizza Equilibrium without tax P Q D1D1 $10.00 500

4. A Tax on Buyers Effects of a $1.00 per unit tax on buyers D1D1 $10.00 500430 P Q D2D2 $11.00 $9.00 Tax 470 Without tax consumers would buy 430 pizzas if the price is $11. For consumers it does not matter if the increase in price is due to price itself or tax. If the market price is $10 but consumers have to pay $1 in tax then at P=$10 they would demand as much as at P=$11 without tax. The same is true for any price. Hence, $1 tax would shift the demand curve down to the left by vertical distance $1.

5. S1S1 D1D1 $10.00 500 430 A Tax on Buyers A tax on buyers shifts the D curve down by the amount of the tax. P Q D2D2 $11.00 P B = $9.50 P S = Tax Effects of a $1.50 per unit tax on buyers The price buyers pay rises, the price sellers receive falls, equilibrium Q falls. The price buyers pay rises, the price sellers receive falls, equilibrium Q falls.

6. 430 S1S1 how the burden of a tax is shared among market participants P Q D1D1 $10.00 500 D2D2 $11.00 P B = $9.50 P S = Tax Because of the tax, buyers pay $1.00 more, sellers get $0.50 less. Because of the tax, buyers pay $1.00 more, sellers get $0.50 less.

7. S1S1 A Tax on Sellers A tax on sellers shifts the S curve up by the amount of the tax. P Q D1D1 $10.00 500 S2S2 430 $11.00 P B = $9.50 P S = Tax Effects of a $1.50 per unit tax on sellers The price buyers pay rises, the price sellers receive falls, equilibrium Q falls.

8. S1S1 What matters is this: A tax drives a wedge between the price buyers pay and the price sellers receive. P Q D1D1 $10.00 500 430 $9.50 $11.00 P B = P S = Tax The effects on P and Q, and the tax incidence are the same whether the tax is imposed on buyers or sellers! incidence 发生率； 影响范围 wedge 楔形物

9. Elasticity and Tax Incidence CASE 1: Supply is more elastic than demand P Q D S Tax Buyers’ share of tax burden Sellers’ share of tax burden Price if no tax PBPB PSPS In this case, buyers bear most of the burden of the tax.

10. CASE 2: Demand is more elastic than supply P Q D S Tax Buyers’ share of tax burden Sellers’ share of tax burden Price if no tax PBPB PSPS In this case, sellers bear most of the burden of the tax.

11. If buyers ’ price elasticity > sellers ’ price elasticity, buyers can more easily leave the market when the tax is imposed, so buyers will bear a smaller share of the burden of the tax than sellers. If sellers ’ price elasticity > buyers ’ price elasticity, the reverse is true.

12. CASE STUDY: Who Pays the Luxury Tax? 1990: Congress adopted a luxury tax on yachts, private airplanes, furs, expensive cars, etc. Goal of the tax: to raise revenue from those who could most easily afford to pay – wealthy consumers. But who really pays this tax?

13. The market for yachts P Q D S Tax Buyers’ share of tax burden Sellers’ share of tax burden PBPB PSPS Demand is price-elastic. In the short run, supply is inelastic. Hence, companies that build yachts pay most of the tax.

14. Review A tax is a wedge between the price buyers pay and the price sellers receive. A tax raises the price buyers pay and lowers the price sellers receive. A tax reduces the quantity bought & sold. These effects are the same whether the tax is imposed on buyers or sellers, so we do not make this distinction in this chapter.

15. QTQT The Effects of a Tax P Q D S Eq ’ m with no tax: price = P E quantity = Q E PSPS PBPB PEPE QEQE Eq ’ m with tax = $T per unit: Sellers receive P S Quantity = Q T Buyers pay P B Size of tax = $T

16. P Q D S Revenue from tax: $ T x Q T PSPS PBPB PEPE QEQE QTQT Size of tax = $T

17. Next, we apply welfare economics to measure the gains and losses from a tax. We determine consumer surplus (CS), producer surplus (PS), tax revenue, and total surplus with and without the tax. Tax revenue can fund beneficial services (e.g. education, roads, police) so we include it in total surplus.

18. P Q D S Without a tax, PEPE QEQE QTQT 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

19. P Q D S PSPS PBPB QEQE QTQT 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

20. P Q D S PSPS PBPB QEQE QTQT A B C D E F C + E is called the deadweight loss (DWL 无谓损 失 ) of the tax, the fall in total surplus that results from a market distortion, such as a tax.

21. P Q D S PSPS PBPB QEQE QTQT Because of the tax, the units between Q T and Q E 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.

22. A C T I V E L E A R N I N G 1 : Analysis of tax A. Compute CS, PS, and total surplus without a tax. B. If $100 tax per ticket, compute CS, PS, tax revenue, total surplus, and DWL. D S P Q $ The market for airplane tickets

23. A C T I V E L E A R N I N G 1 : Answers to A D S CS = ½ x $200 x 100 = $10,000 P Q $ total surplus = $10,000 + $10,000 = $20,000 PS = ½ x $200 x 100 = $10,000 P = The market for airplane tickets

24. A C T I V E L E A R N I N G 1 : Answers to B D S CS = ½ x $150 x 75 = $5,625 P Q $ total surplus = $18,750 PS = $5,625 tax revenue = $100 x 75 = $7,500 DWL = $1,250 P S = P B = A $100 tax on airplane tickets

25. What Determines the Size of the DWL? Which goods or services should government tax to raise the revenue it needs? –One answer: those with the smallest DWL. When is the DWL small vs. large? –It depends on the price elasticities of supply and demand. Recall: The price elasticity of demand (or supply) measures how much Q D (or Q S ) changes when P changes.

26. the DWL of a tax is small. When supply is inelastic, DWL and the Elasticity of Supply P Q D S Size of tax

27. The more elastic is supply, the larger is the DWL. P Q D S Size of tax

28. the DWL of a tax is small. DWL and the Elasticity of Demand When demand is inelastic, P Q D S Size of tax

29. P Q D S The more elastic is demand, the larger is the DWL.

30. Why Elasticity Affects the Size of DWL A tax distorts the market outcome: consumers buy less, producers sell less, market Q is below the surplus-maximizing Q. Elasticity measures how much buyers and sellers respond to changes in price, and therefore determines how much the tax distorts the market outcome.

31. A C T I V E L E A R N I N G 2 : Elasticity and DWL of a tax Would the DWL of a tax be larger if the tax were on A. Rice Krispies or sunscreen? B. Hotel rooms in the short run or hotel rooms in the long run? C. Groceries or meals at fancy restaurants?

32. A C T I V E L E A R N I N G 2 : Answers A.Rice Krispies or sunscreen Rice Krispies has many more close substitutes than sunscreen, so demand for Rice Krispies is more price-elastic than demand for sunscreen. So, a tax on Rice Krispies would cause a larger DWL than a tax on sunscreen.

33. A C T I V E L E A R N I N G 2 : Answers B.Hotel rooms in the short run or long run The price elasticities of demand and supply for hotel rooms are larger in the long run than in the short run. So, a tax on hotel rooms would cause a larger DWL in the long run than in the short run.

34. A C T I V E L E A R N I N G 2 : Answers C.Groceries or meals at fancy restaurants Groceries are more of a necessity and therefore less price-elastic than meals at fancy restaurants. So, a tax on restaurant meals would cause a larger DWL than a tax on groceries.

35. A C T I V E L E A R N I N G 3 : Discussion question The government must raise tax revenue to pay for schools, police, etc. To do this, it can either tax groceries or meals at fancy restaurants. Which should it tax?

36. How Big Should the Government Be? A bigger government provides more services, but requires higher taxes, which cause DWLs. The larger the DWL from taxation, the greater the argument for smaller government. The tax on labor income is especially important; it ’ s the biggest source of government revenue. For many workers, the marginal tax rate (the tax on the last dollar of earnings) is almost 50%. How big is the DWL from this tax? It depends on elasticity ….

37. If labor supply is inelastic, then this DWL is small. Some economists believe labor supply is inelastic, arguing that most workers work full time regardless of the wage.

38. Other economists believe labor taxes are highly distorting because some groups of workers have elastic supply and can respond to incentives: –Many workers can adjust their hours, e.g. by working overtime. –Many families have a 2 nd earner with discretion over whether and how much to work. –Many elderly choose when to retire based on the wage they earn. –Some people work in the “ underground economy ” to evade high taxes. discretion 判断力 evade 逃避

39. The Effects of Changing the Size of the Tax Policymakers often change taxes, raising some and lowering others. What happens to DWL and tax revenue when taxes change?

40. Q2Q2 Q1Q1 DWL and the Size of the Tax P Q D S causes the DWL to more than double. Doubling the tax 2T2T T Initially, the tax is T per unit. initial DWL new DWL

41. Q3Q3 P Q D S Q1Q1 3T3T T causes the DWL to more than triple. Tripling the tax Initially, the tax is T per unit. initial DWL new DWL

42. 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.

43. Q2Q2 Revenue and the Size of the Tax P Q D S Q1Q1 PBPB PSPS PBPB PSPS 2T2T T When the tax is small, increasing it causes tax revenue to rise.

44. Q3Q3 P Q D S Q2Q2 PBPB PSPS PBPB PSPS 3T3T 2T2T When the tax is larger, increasing it causes tax revenue to fall.

45. The Laffer curve shows the relationship between the size of the tax and tax revenue. Tax size Tax revenue The Laffer curve

46. SUMMARY A tax on a good reduces the welfare of buyers and sellers. This welfare loss usually exceeds the revenue the tax raises for the government. The fall in total surplus (consumer surplus, producer surplus, and tax revenue) is called the deadweight loss (DWL) of the tax. A tax has a DWL because it causes consumers to buy less and producers to sell less, thus shrinking the market below the level that maximizes total surplus.

47. The price elasticities of demand and supply measure how much buyers and sellers respond to price changes. Therefore, higher elasticities imply higher DWLs. An increase in the size of a tax causes the DWL to rise even more. An increase in the size of a tax causes revenue to rise at first, but eventually revenue falls because the tax reduces the size of the market.