【正文】 ? 多數(shù)決定機(jī)制是無效率的，因?yàn)樗鼘⒚總€(gè)投票者的偏好視為等同； ? 一個(gè)有效的結(jié)果應(yīng)建立在以每個(gè)公民的偏好強(qiáng)度為權(quán)數(shù)來衡量其投票的基礎(chǔ)上。 83 D1 D2 D When a good is nonrival, the social marginal benefit of consumption (D) , is determined by vertically summing the individual demand curves for the good. Efficient Public Good Provision Output 0 Benefits (dollars) 1 2 3 4 5 6 7 8 10 9 $ $ $ Marginal Cost $ Efficient output occurs where MC = MB at 2 units of output. MB is $ + $ or $. 84 對公共產(chǎn)品的私人偏好 ? 政府生產(chǎn)公共產(chǎn)品較有利，是因?yàn)檎軌蛲ㄟ^征收稅費(fèi)來支付生產(chǎn)成本。 81 Common Property Resources Fish per Month Benefits, Costs ($ per fish) Demand However, private costs underestimate true cost. The efficient level of fish/month is F* where MSC = MB (D) Marginal Social Cost F* Private Cost FC Without control the number of fish/month is FC where PC = MB. 82 公共產(chǎn)品 ? 公共產(chǎn)品的特點(diǎn)： ? 非競爭性：給定任何生產(chǎn)水平，向一個(gè)額外消費(fèi)者提供該商品的邊際成本為 0； ? 非排他性：無法禁止人們消費(fèi)該種商品。 79 三、公共物品和公共資源 ? 私人物品： ? 排他性：只有對商品支付價(jià)格的人才能使用該商品； ? 競用性：如某人已使用了某個(gè)商品，則其他人不能再同時(shí)使用該商品。 ? 議價(jià)與經(jīng)濟(jì)效率 ? 當(dāng)受外部性影響的群體較少并且產(chǎn)權(quán)良好界定時(shí)，經(jīng)濟(jì)效率將在沒有政府干預(yù)的情況下實(shí)現(xiàn)。 73 Firm 2’s Reduced Abatement Costs Firm 1’s Increased Abatement Costs MCA1 MCA2 The Case for Fees Level of Emissions 2 4 6 Fee per Unit of Emissions 0 1 2 3 4 5 6 7 8 9 10 11 12 13 1 3 5 14 The cost minimizing solution would be an abatement of 6 for firm 1 and 8 for firm 2 and MCA1= MCA2 = $3. The impact of a standard of abatement of 7 for both firms is illustrated. Not efficient because MCA2 MCA1. If a fee of $3 was imposed Firm 1 emissions would fall by 6 to 8. Firm 2 emissions would fall by 8 to 6. MCA1 = MCA2: efficient solution. 74 ABC is the increase in social cost less the decrease in abatement cost. Marginal Social Cost Marginal Cost of Abatement The Case for Standards Level of Emissions Fee per Unit of Emissions 0 2 4 6 8 10 12 14 16 2 4 6 8 10 12 14 16 E Based on inplete information standard is 9 (% decrease). ADE ABC D A B C Based on inplete information fee is $7 (% reduction). Emission increases to 11. 75 糾正市場失靈的方法 ? 可轉(zhuǎn)讓排放許可證 ? 許可證幫助建立起一個(gè)外部性的競爭市場。 ? 排放費(fèi)： ? 對廠商每單位廢氣進(jìn)行收費(fèi)。 ? 邊際社會(huì)成本： MSC=MC+MEC 66 MC S = MCI D P1 Aggregate social cost of negative externality P1 q1 Q1 MSC MSCI When there are negative externalities, the marginal social cost MSC is higher than the marginal cost. External Costs Firm output Price Industry output Price MEC MECI The differences is the marginal external cost MEC. q* P* Q* The industry petitive output is Q1 while the efficient level is Q*. The profit maximizing firm produces at q1 while the efficient output level is q*. 67 外部性導(dǎo)致無效率 ? 負(fù)外部性使一些低效率的廠商繼續(xù)保留在行業(yè)內(nèi)，從而導(dǎo)致長期尺度上的過量生產(chǎn)。 ? 正外部性： ? 一個(gè)群體的行為給其他群體帶來收益。 ? 不完全信息： ? 信息缺陷導(dǎo)致資源流動(dòng)障礙。 ? 絕對優(yōu)勢： ? 在所有商品生產(chǎn)上都占有絕對優(yōu)勢的國家將不會(huì)在所有商品生產(chǎn)上占有相對優(yōu)勢。 ? 50 Production Possibilities Frontier Food (Units) Clothing (units) OF OC are extremes. Why is the production possibilities frontier downward sloping? Why is it concave? B, C, D are other possible binations. A A is inefficient. ABC triangle is also inefficient due to labor market distortions. 60 100 OF OC B C D 51 Production Possibilities Frontier Food (Units) Clothing (units) 60 100 OF OC A B C D B 1C 1F D 2C 1F MRT = MCF/MCC The marginal rate of transformation (MRT) is the slope of the frontier at each point. 52 產(chǎn)出效率 ? 產(chǎn)出效率： ? 應(yīng)以最小成本生產(chǎn)； ? 并且生產(chǎn)的商品組合應(yīng)與人們購買它們的意愿相一致。 47 60F 50F 40L 30L Labor in clothing production Efficiency in Production 50L 0C 0F 30K Capital in clothing production 20L 10L 20K 10K 10L 20L 30L 40L 50L Capital in food production 10K 20K 30K 30C 25C 10C 80F Labor in Food Production B C D A Each point measures inputs to the production A: 35L and 5KFood B: 15L and 25KClothing Each isoquant shows input binations for a given output Food: 50, 60, 80 Clothing: 10, 25, 30 Efficiency ?A is inefficient ?Shaded area is preferred to A ?B and C are efficient ?The production contract curve shows all binations that are efficient 48 競爭性投入品市場的生產(chǎn)均衡 ? 據(jù)上圖： ? 競爭性市場產(chǎn)生有效生產(chǎn)點(diǎn)。換言之，公平與效率并非絕對矛盾。