فشل السوق والتدخل الحكومي
بيرون إيديكلر · International A-Level · Economics الموضوع 2 5:43 سرد باللغة الإنجليزية · ترجمة مدمجة بالإنجليزية + الصينية
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النص الصوتي
Markets sometimes fail, producing too much or too little.
市场有时会失灵，生产过多或过少。
Government intervenes to correct them.
政府进行干预加以纠正。
But intervention can fail too, leaving a net welfare loss.
但干预本身也可能失败，造成净福利损失。
Five sources.
五个来源。
Externalities leave third-party costs and benefits unpriced.
外部性使第三方成本和收益没有被定价。
Public goods attract free riders.
公共物品引来搭便车者。
Information gaps let one side know more.
信息缺口使一方知道得更多。
Moral hazard makes the protected take more risk.
道德风险使受保护的一方承担更多风险。
And speculative bubbles detach prices from fundamentals.
投机泡沫使价格脱离基本面。
Social cost is private cost plus external cost; social benefit is private benefit plus external benefit.
社会成本等于私人成本加外部成本；社会收益等于私人收益加外部收益。
Externalities arise in production, such as factory emissions or training that other firms use, and in consumption, such as congestion from driving or vaccination.
外部性产生于生产，例如工厂排放或被其他企业利用的培训；也产生于消费，例如开车造成的拥堵或接种疫苗。
demand is marginal private benefit, and supply is marginal private cost: the market trades at 100 and 20.
需求是边际私人收益，供给是边际私人成本：市场在 100 和 20 处成交。
An external cost of 6 per unit puts marginal social cost above.
每单位 6 的外部成本使边际社会成本位于上方。
It crosses social benefit at 92 and 24.
它与社会收益相交于 92 和 24。
Between 92 and 100 each unit costs society more than it is worth: the welfare loss triangle is 24.
在 92 到 100 之间，每一单位给社会带来的成本都高于其价值：福利损失三角形为 24。
Marginal social cost is Q over 4 minus 5, plus 6: Q over 4 plus 1.
边际社会成本等于 Q 除以 4 减 5，再加 6：Q 除以 4 加 1。
Set it equal to 70 minus Q over 2: Q is 92 and P is 24.
令它等于 70 减 Q 的一半：Q 为 92，P 为 24。
The loss is one half times 8 times 6: 24 a day.
损失为二分之一乘 8 乘 6，即每天 24。
Now the external benefit of 6 lifts social benefit above private benefit.
现在 6 的外部收益使社会收益高于私人收益。
The market stops at 100 where private benefit meets private cost, but the optimum is 108.
市场停在私人收益等于私人成本的 100 处，但社会最优是 108。
The welfare GAIN available between them is again one half times 8 times 6: 24.
两者之间可获得的福利增益同样是二分之一乘 8 乘 6，即 24。
Five contexts.
五个情境。
Transport: congestion and pollution.
交通：拥堵和污染。
Health: vaccination, and passive smoking.
健康：接种疫苗，以及被动吸烟。
Education: spillovers from a skilled workforce.
教育：技术劳动力带来的溢出效应。
Environment: emissions.
环境：排放。
Financial: the risk that spreads when a bank fails.
金融：银行倒闭时扩散的风险。
Private goods are rival and excludable: one person's sandwich is gone, and non-payers can be stopped.
私人物品具有竞争性和排他性：一个人的三明治吃掉就没了，不付钱的人可以被拒之门外。
Public goods are non-rival and non-excludable: a flood defence protects everyone at once and cannot be withheld.
公共物品具有非竞争性和非排他性：防洪设施同时保护所有人，无法不让某人享用。
Because a public good is non-excludable, nobody can be charged.
因为公共物品具有非排他性，无法向任何人收费。
Everyone free rides, so private firms cannot cover costs and supply nothing at all.
人人都搭便车，私营企业无法收回成本，根本不会提供。
The state must provide it.
只能由国家提供。
When information is asymmetric, one side knows more.
信息不对称时，一方知道得更多。
Patients cannot judge treatment in healthcare; students cannot judge course quality in education; complexity hides value in pensions; and insurers know less than the insured.
在医疗中，病人无法判断治疗；在教育中，学生无法判断课程质量；养老金的复杂性掩盖了价值；保险公司比投保人知道得少。
Moral hazard arises after a contract: the protected party takes more risk.
道德风险出现在签约之后：受保护的一方承担更多风险。
Insured drivers drive less carefully.
投保的司机开车更不小心。
Consumers then pay higher premiums, and governments face bailout bills.
于是消费者支付更高的保费，政府面临救助账单。
A bubble begins when buyers buy only to resell.
当买家只为转售而购买时，泡沫就开始了。
Prices detach from fundamentals, rising faster and faster.
价格脱离基本面，越涨越快。
Then they crash, hurting consumers, producers, workers and governments.
然后崩盘，伤害消费者、生产者、工人和政府。
The methods.
方法如下。
An indirect tax equal to the external cost of 6 moves output to 92 at 24.
与 6 的外部成本相等的间接税使产量移到 92、价格 24。
A subsidy of 6 lifts output to 108.
6 的补贴使产量升到 108。
Maximum and minimum prices.
最高价格和最低价格。
Tradeable pollution permits.
可交易污染许可证。
Property rights that let victims sue.
让受害者能起诉的产权。
State provision and regulation.
国家提供和监管。
And information that closes the gaps.
以及弥补信息缺口的信息提供。
A maximum price of 16, below equilibrium, makes goods affordable, but Qd is 108 and Qs only 84: a shortage of 24.
最高价格 16 低于均衡价格，让商品更便宜，但需求量 108，供给量只有 84：短缺 24。
A minimum price of 24 protects producers, but Qs is 116 and Qd only 92: a surplus of 24.
最低价格 24 保护生产者，但供给量 116，需求量只有 92：过剩 24。
The cap fixes total emissions at 84 permits, so supply is vertical.
上限把排放总量固定在 84 个许可证，所以供给是垂直的。
demand sets the permit price: 28.
需求决定许可证价格：28。
Firms that can cut pollution cheaply sell their permits to firms for whom cutting is dear.
减排成本低的企业把许可证卖给减排成本高的企业。
Government failure is intervention that leaves a net welfare loss.
政府失灵是造成净福利损失的干预。
Causes: information gaps, so a tax set too high overshoots; unintended consequences such as black markets; administrative costs; lack of incentives for state providers; and moral hazard.
原因：信息缺口，税定得太高会矫枉过正；意外后果，如黑市；行政成本；国家提供者缺乏激励；以及道德风险。
Before the charge, 100,000 vehicles a day entered the zone.
收费前，每天有 10 万辆车进入收费区。
Traffic fell by about 18%, so 100,000 times 0.82 is 82,000.
交通量下降约百分之 18，所以 10 万乘 0.82 等于 8.2 万。
At 5 pounds each, revenue is 410,000 pounds a day.
每辆 5 英镑，每天收入 41 万英镑。
Road pricing targets the externality, funds buses and rail, and worked quickly, but a flat charge is regressive.
道路收费针对外部性，为公交和铁路筹资，而且见效快，但统一收费具有累退性。
Building roads adds capacity and is popular, but new roads fill with induced demand, and they are costly, slow and polluting.
修路增加通行能力，也受欢迎，但新路会被诱发的需求填满，而且成本高、耗时长、有污染。
Judgement: pricing suits dense city centres with real public-transport alternatives.
判断：收费适合有可靠公共交通替代的密集市中心。
Check yourself.
自我检测。
With an external cost of 6, the welfare loss is one half times 8 times 6: 24.
外部成本为 6 时，福利损失为二分之一乘 8 乘 6，等于 24。
With an external benefit of 6, the optimum is 108.
外部收益为 6 时，社会最优为 108。
A maximum price of 16 leaves a shortage of 24.
最高价格 16 造成短缺 24。
A public good is non-rival and non-excludable.
公共物品具有非竞争性和非排他性。
And government failure is a net welfare loss.
政府失灵是净福利损失。