曼昆经济学原理Cha.ppt

1、Supply, Demand, and Government Policies,1, 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use

2、.,Govt Controls on Prices,Price ceiling (maximum price) A legal maximum on the price at which a good can be sold (eg.) rent control Price floor (minimum price) A legal minimum on the price at which a good can be sold (eg.) minimum wage,2, 2012 Cengage Learning. All Rights Reserved. May not be copied

3、, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.,Controls on Prices,How price ceilings affect market outcomes? Not binding (above the equilibrium price

4、) No effect on the price or quantity sold Binding constraint Below the equilibrium price Shortage arises Sellers must ration the scarce goods What kind of rationing mechanisms?,3, 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for u

5、se as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.,Figure 1,4, 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license

6、distributed with a certain product or service or otherwise on a password-protected website for classroom use.,A Market with a Price Ceiling,Price of Ice-Cream Cones,Demand,100,(a) A Price Ceiling That Is Not Binding,In panel (a), the government imposes a price ceiling of $4. Because the price ceilin

7、g is above the equilibrium price of $3, the price ceiling has no effect, and the market can reach the equilibrium of supply and demand. In this equilibrium, quantity supplied and quantity demanded both equal 100 cones. In panel (b), the government imposes a price ceiling of $2. Because the price cei

8、ling is below the equilibrium price of $3, the market price equals $2. At this price, 125 cones are demanded and only 75 are supplied, so there is a shortage of 50 cones.,(b) A Price Ceiling That Is Binding,3,Supply,Equilibrium price,Equilibrium quantity,Price of Ice-Cream Cones,Demand,$3,Supply,Equ

9、ilibrium price,75,Quantity demanded,Quantity supplied,125,Lines at the gas pump,Price ceiling on gasoline Before OPEC raised the price of crude oil (1973), Equilibrium price was below the price ceiling No effect on the market When the price of crude oil rose Decrease in the supply of gasoline Equili

10、brium price above the price ceiling Binding price ceiling Severe shortage Long lines at gas stations,5, 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service o

11、r otherwise on a password-protected website for classroom use.,Figure 2,6, 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-pro

12、tected website for classroom use.,The Market for Gasoline with a Price Ceiling,Demand,Q1,(a) The Price Ceiling On Gasoline Is Not Binding,Panel (a) shows the gasoline market when the price ceiling is not binding because the equilibrium price, P1, is below the ceiling. Panel (b) shows the gasoline ma

13、rket after an increase in the price of crude oil (an input into making gasoline) shifts the supply curve to the left from S1 to S2. In an unregulated market, the price would have risen from P1 to P2. The price ceiling, however, prevents this from happening. At the binding price ceiling, consumers ar

14、e willing to buy QD, but producers of gasoline are willing to sell only QS. The difference between quantity demanded and quantity supplied, QD QS, measures the gasoline shortage.,(b) The Price Ceiling On Gasoline Is Binding,P1,Supply, S1,Price ceiling,1. Initially, the price ceiling is not binding ,

15、Demand,Q1,P1,S1,Price ceiling,2but when supply falls,S2,P2,3the price ceiling becomes binding,QS,QD,Rent control in the short run and the long run,Price ceiling: rent control Government - ceiling on housing rents Goal: help the poor, with more affordable housing Critique Highly inefficient way to he

16、lp the poor to raise their standard of living,7, 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classro

17、om use.,Rent control in the short run and the long run,Effects in the short run Supply and demand for housing are relatively inelastic Small shortage Reduced rents,8, 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitt

18、ed in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.,Rent control in the short run and the long run,Adverse effects in the long run Supply and demand are more elastic Landlords Are not building new apartments Fail to maintain e

19、xisting ones People Try to find their own apartments Induce more people to move into a city Large shortage of housing, with rationing mechanisms inevitable Long waiting lists Preference to tenants without children (discrimination) Bribes to building superintendents,9, 2012 Cengage Learning. All Righ

20、ts Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.,Rent control in the short run and the long run,People respond to incenti

21、ves Free markets Landlords clean and safe buildings Higher prices Rent control Shortages & waiting lists Landlords lose their incentive to respond to tenants concerns Tenants get lower-quality housing with lower rents Policymakers additional regulations Difficult and costly to enforce,10, 2012 Cenga

22、ge Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.,Figure 3,11, 2012 Cengage Learning. All Rights Rese

23、rved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.,Rent Control in the Short Run and in the Long Run,Demand,(a) Rent Control in th

24、e Short Run (supply and demand are inelastic),Panel (a) shows the short-run effects of rent control: Because the supply and demand for apartments are relatively inelastic, the price ceiling imposed by a rent-control law causes only a small shortage of housing. Panel (b) shows the long-run effects of

25、 rent control: Because the supply and demand for apartments are more elastic, rent control causes a large shortage.,(b) Rent Control in the Long Run (supply and demand are elastic),Supply,Controlled rent,Demand,Supply,Controlled rent,Controls on Prices,How price floors affect market outcomes Not bin

26、ding Below the equilibrium price No effect on the market Binding constraint Above the equilibrium price Surplus Some sellers are unable to sell what they want,12, 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted i

27、n a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.,Figure 4,13, 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with

28、 a certain product or service or otherwise on a password-protected website for classroom use.,A Market with a Price Floor,Demand,100,(A) A Price Floor That Is Not Binding,In panel (a), the government imposes a price floor of $2. Because this is below the equilibrium price of $3, the price floor has

29、no effect. The market price adjusts to balance supply and demand. At the equilibrium, quantity supplied and quantity demanded both equal 100 cones. In panel (b), the government imposes a price floor of $4, which is above the equilibrium price of $3. Therefore, the market price equals $4. Because 120

30、 cones are supplied at this price and only 80 are demanded, there is a surplus of 40 cones.,(B) A Price Floor That Is Binding,$3,Supply,Equilibrium price,Equilibrium quantity,Demand,3,Supply,Equilibrium price,80,Quantity supplied,Quantity demanded,120,The minimum wage,Price floor: minimum wage Lowes

31、t wage for labor that any employer may pay Market for labor Workers supply of labor Firms demand for labor If minimum wage is above equilibrium Unemployment Higher income for workers who have jobs Lower income for workers who cannot find jobs Size of the unemployment depend on the elasticities,14, 2

32、012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.,The minimum wage,Impact of the minimum wag

33、e Highly skilled and experienced workers Not affected, their equilibrium wages are well above the minimum wage Minimum wage - not binding Least skilled and least experienced workers (eg. Teenage workers) Low equilibrium wages Willing to accept a lower wage in exchange for on-the-job training Minimum

34、 wage binding,15, 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.,Figure 5,16, 2012 Cenga

35、ge Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.,How the Minimum Wage Affects the Labor Market,Labor

36、 demand,Equilibrium employment,(a) A Free Labor Market,Panel (a) shows a labor market in which the wage adjusts to balance labor supply and labor demand. Panel (b) shows the impact of a binding minimum wage. Because the minimum wage is a price floor, it causes a surplus: The quantity of labor suppli

37、ed exceeds the quantity demanded. The result is unemployment.,(b) A Labor Market with a Binding Minimum Wage,Equilibrium wage,Labor supply,Minimum wage,Quantity demanded,Quantity supplied,Labor demand,Labor supply,Controls on Prices,Evaluating the price controls Markets are usually a good way to org

38、anize economic activity Economists usually oppose price controls Governments can sometimes improve market outcomes Want to use price controls Aim at helping the poor Often hurt those they are trying to help Other ways of helping those in need Rent subsidies or Wage subsidies,17, 2012 Cengage Learnin

39、g. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.,Taxes,Tax incidence How is the burden of a tax shared among p

40、articipants in a market Tax levied on sellers of a good Immediate impact on sellers - shift in supply Supply curve shifts left Higher equilibrium price Lower equilibrium quantity The tax reduces the size of the market,18, 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or dup

41、licated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.,Figure 6,19, 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part

42、, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.,A Tax on Sellers,Demand, D1,90,When a tax of $0.50 is levied on sellers, the supply curve shifts up by $0.50 from S1 to S2. The equilibrium quantit

43、y falls from 100 to 90 cones. The price that buyers pay rises from $3.00 to $3.30. The price that sellers receive (after paying the tax) falls from $3.00 to $2.80. Even though the tax is levied on sellers, buyers and sellers share the burden of the tax.,S1,S2,100,$3.30,3.00,2.80,Price buyers pay,Pri

44、ce without tax,Price sellers receive,A tax on sellers shifts the supply curve upward by the size of the tax ($0.50).,Equilibrium without tax,Equilibrium with tax,Taxes,Tax levied on sellers of a good Taxes discourage market activity Buyers and sellers share the burden of tax Buyers pay more Worse of

45、f Sellers receive less Get the higher price but pay the tax, with effective price fall Worse off,20, 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or o

46、therwise on a password-protected website for classroom use.,Taxes,Tax levied on buyers of a good Initial impact on the demand Demand curve shifts left Lower equilibrium price Lower equilibrium quantity The tax reduces the size of the market,21, 2012 Cengage Learning. All Rights Reserved. May not be

47、copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.,Figure 7,22, 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicat

48、ed, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.,A Tax on Buyers,D1,90,When a tax of $0.50 is levied on buyers, the demand curve shifts down by $0.50 from D1 to D2. The equi

49、librium quantity falls from 100 to 90 cones. The price that sellers receive falls from $3.00 to $2.80. The price that buyers pay (including the tax) rises from $3.00 to $3.30. Even though the tax is levied on buyers, buyers and sellers share the burden of the tax.,Supply, S1,100,$3.30,3.00,2.80,Pric

50、e buyers pay,Price without tax,Price sellers receive,A tax on buyers shifts the demand curve downward by the size of the tax ($0.50).,Equilibrium without tax,Equilibrium with tax,D2,Taxes,Tax levied on buyers of a good Buyers and sellers share the burden of tax Sellers get a lower price Worse off Bu

51、yers pay a lower market price Effective price (with tax) rises Worse off,23, 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-p

52、rotected website for classroom use.,Can congress distribute the burden of a payroll tax?,Lawmakers By law, the tax burden: Half of the tax paid by firms out of firms revenue Half of the tax - paid by workers deducted from workers paychecks May decide whether a tax comes from the buyers pocket or fro

53、m the sellers Cannot legislate the true burden of a tax Tax incidence Determined by the forces of supply and demand,24, 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain prod

54、uct or service or otherwise on a password-protected website for classroom use.,Can congress distribute the burden of a payroll tax?,Payroll taxes Deduction from the amount you earned Tax incidence analysis Payroll tax = tax on a good (labor), with its price (= wage) Introduce payroll tax Wage receiv

55、ed by workers falls Wage paid by firms rises Workers and firms share the tax burden,25, 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a

56、 password-protected website for classroom use.,Figure 8,26, 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website

57、for classroom use.,A Payroll Tax,Labor demand,Labor supply,Wage firms pay,Wage without tax,Wage workers receive,A payroll tax places a wedge between the wage that workers receive and the wage that firms pay. Comparing wages with and without the tax, you can see that workers and firms share the tax b

58、urden. This division of the tax burden between workers and firms does not depend on whether the government levies the tax on workers, levies the tax on firms, or divides the tax equally between the two groups.,Taxes,Elasticity and tax incidence Tax burden Falls more heavily on the side of the market

59、 that is less elastic Small elasticity of demand (inelastic demand) Buyers do not have good alternatives to consuming this good Small elasticity of supply (inelastic supply) Sellers do not have good alternatives to producing this good,27, 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.,Figure 9,28, 2012 Cengage Learning. All Rights Reserved. May not be