Externalities and social costs and benefits · 外部性与社会成本和利益
| English | 中文 | Pinyin · 拼音 |
|---|---|---|
| marginal social cost/ˈmɑːdʒɪnl ˈsəʊʃl kɒst/ | 边际社会成本 | biān jì shè huì chéng běn |
| marginal private cost/ˈmɑːdʒɪnl ˈpraɪvət kɒst/ | 边际私人成本 | biān jì sī rén chéng běn |
| marginal social benefit/ˈmɑːdʒɪnl ˈsəʊʃl ˈbenɪfɪt/ | 边际社会收益 | biān jì shè huì shōu yì |
| social optimum/ˈsəʊʃl ˈɒptɪməm/ | 社会最优 | shè huì zuì yōu |
| deadweight welfare loss/ˈdedweɪt ˈwelfeə lɒs/ | 无谓损失 | wú wèi sǔn shī |
| tradable pollution permits/ˈtreɪdəbl pəˈluːʃn ˈpɜːmɪts/ | 可交易污染许可 | kě jiāo yì wū rǎn xǔ kě |
The full cost of a decision
- A factory's price covers its wages and materials — but not the asthma its smoke causes downwind. Society pays that hidden bill.
- Weighing all the costs and benefits — social, not just private — is how economists judge whether a market produces the right amount.
一个决策的全部成本
- 一个工厂的价格涵盖它的工资和材料——但不涵盖它的烟雾给下风处造成的哮喘。社会付那张隐藏的账单。
- 权衡所有的成本和利益——社会的,不只是私人的——是经济学家判断一个市场是否生产正确数量的方式。
Marginal social cost (MSC) equals marginal private cost plus the: · 边际社会成本(MSC)等于边际私人成本加上:
MSC = MPC + external cost imposed on third parties. · MSC = MPC + 加在第三方身上的外部成本。
The social optimum is where: · 社会最优在以下之处:
Society is best off where marginal social cost equals marginal social benefit. · 社会在边际社会成本等于边际社会利益之处最好。
Marginal social benefit = marginal private benefit + the external . · 边际社会利益 = 边际私人利益 + 外部。
MSB = MPB + external benefit. · MSB = MPB + 外部利益。
Social cost and benefit
- Marginal social cost 边际社会成本 (MSC) = marginal private cost 边际私人成本 + the external cost.
- Marginal social benefit 边际社会收益 (MSB) = marginal private benefit + the external benefit.
- The social optimum 社会最优 is where MSC = MSB.
社会成本与利益
- 边际社会成本(marginal social cost,MSC)= 边际私人成本 + 外部成本。
- 边际社会利益(marginal social benefit,MSB)= 边际私人利益 + 外部利益。
- 社会最优是 MSC = MSB 之处。
Externalities shift the social curve · 外部性移动社会曲线
A negative externality means the social cost is above the private supply curve; the free-market quantity is then too high. · 一个负外部性意味着社会成本在私人供给曲线之上;自由市场数量于是太高。
The gap between the market outcome and the social optimum creates a deadweight welfare loss. · 市场结果与社会最优之间的差距造成一个无谓福利损失。
Over- or under-production relative to the optimum wastes welfare. · 相对于最优的过度或不足生产浪费福利。
Welfare loss
- A free market produces where private cost = private benefit — usually not the social optimum.
- The gap creates a deadweight welfare loss 无谓损失 (the shaded triangle).
With a negative externality the market over-produces; the welfare-loss triangle measures the cost to society.
福利损失
- 一个自由市场在私人成本 = 私人利益之处生产——通常不是社会最优。
- 那个差距造成一个无谓福利损失(阴影三角形)。
有一个负外部性时,市场过度生产;福利损失三角形测量给社会的成本。
Match each externality to a correcting policy. · 把每个外部性与一项纠正政策配对。
Tax/permits curb over-production; subsidies boost under-provided goods. · 税/许可证抑制过度生产;补贴提振供给不足的商品。
Correcting it
- Negative externalities: taxes, regulation, tradable pollution permits 可交易污染许可.
- Positive externalities: subsidies, free provision, information campaigns.
Private optimum ≠ social optimum. The market clears where private marginal cost = private marginal benefit. Add the externality and the social optimum is at a different quantity — that gap is the failure.
纠正它
- 负外部性:税收、监管、可交易的污染许可证。
- 正外部性:补贴、免费供给、信息宣传。
私人最优 ≠ 社会最优。 市场在私人边际成本 = 私人边际利益之处出清。加上外部性,社会最优在一个不同的数量——那个差距就是失灵。
You've got it
- MSC = MPC + external cost; MSB = MPB + external benefit
- the social optimum is MSC = MSB; the market misses it → deadweight welfare loss
- correct with taxes/permits (negative) or subsidies (positive)
你掌握了
- MSC = MPC + 外部成本;MSB = MPB + 外部利益
- 社会最优是 MSC = MSB;市场错失它 → 无谓福利损失
- 用税收/许可证(负的)或补贴(正的)纠正