The macroeconomy (A Level)
A-Level Economics Topic 9 8:33 English narration · English + 中文 subtitles burned in
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Transcript
Look at one building going up.
看这一栋正在盖起来的楼。
Someone is paying for steel, for concrete, for wages.
有人在为钢材、混凝土和工资付钱。
But the story does not stop there.
但故事并没有到此为止。
The builders take those wages home and spend them.
建筑工人把工资带回家，又花了出去。
The shops they spend in pay their own staff.
他们光顾的商店再去支付自己员工的工资。
One new project keeps rippling outward, long after the first payment is made.
一个新项目会不断向外扩散，远在第一笔钱付出之后。
Topic nine: the macroeconomy at A Level. Four ideas. How spending multiplies. How growth is weighed against the environment. Why jobs and prices pull against each other. And what money really is. Let's begin.
第九专题：A Level 阶段的宏观经济。 四个主题：支出如何被放大； 增长如何与环境相权衡；为什么就业与物价互相牵制；以及货币究竟是什么。 让我们开始吧。
A quick recall first.
先快速回顾一下。
In the circular flow of income, households supply labour, firms pay wages, rent and profit, and households spend it back on goods.
在收入循环流中，家庭提供劳动，企业支付工资、租金和利润， 家庭又把这些钱花在商品上。
But the loop is not sealed.
但这个循环不是封闭的。
Injections add money in: investment, government spending and exports.
注入把钱加进来：投资、政府支出和出口。
Leakages take it out: saving, taxation and imports.
漏出把钱抽出去：储蓄、税收和进口。
An injection raises income by more than itself.
一笔注入使收入增加的幅度大于它本身。
One hundred pounds is injected.
注入一百英镑。
Whoever receives it spends eighty percent, so eighty pounds becomes someone else's income.
收到钱的人花掉百分之八十，于是八十英镑成为另一个人的收入。
They spend eighty percent of that, and so on.
他们再花掉其中的百分之八十，如此下去。
That fraction is the marginal propensity to consume.
这个比例就是边际消费倾向。
Every round is smaller, but they all add up.
每一轮都更小，但它们全部累加起来。
The rest leaks out of the circular flow.
其余部分从循环流中漏出。
Income is either spent or saved, so the marginal propensity to consume plus the marginal propensity to save always equals one.
收入不是被花掉就是被储蓄， 所以边际消费倾向加上边际储蓄倾向永远等于一。
A bigger propensity to consume means smaller leakages, so a bigger multiplier.
更大的消费倾向意味着更小的漏出，从而更大的乘数。
Imports leak too: the marginal propensity to import is another leakage.
进口也会漏出：边际进口倾向是另一种漏出。
The more that leaks — saving, tax, or imports — the smaller the multiplier.
漏出越多——储蓄、税收或进口——乘数就越小。
Let's do it properly.
我们来正式做一遍。
The marginal propensity to consume is zero point eight.
边际消费倾向是零点八。
Find the multiplier, then the effect of a ten billion pound rise in investment.
求乘数，再求投资增加一百亿英镑的影响。
Step one: income is either spent or saved, so the propensity to save is zero point two.
第一步：收入不是被花掉就是被储蓄，所以边际储蓄倾向是零点二。
Step two: the multiplier is one over one minus zero point eight, which is one over zero point two, so five.
第二步：乘数等于一除以一减零点八，也就是一除以零点二，等于五。
Step three: five times ten billion.
第三步：五乘以一百亿。
National income rises by fifty billion pounds.
国民收入增加五百亿英镑。
One warning: near full capacity that is mostly inflation, not real output.
一个提醒：在接近满负荷时，那主要是通货膨胀，而不是真实产出。
The multiplier is not the only link.
乘数并不是唯一的联系。
The accelerator says investment depends on the rate of change of output: when demand rises fast, firms rush to add machines and buildings, so investment jumps; when demand merely stays high, it falls back.
加速数说，投资取决于产出的变化率： 当需求快速上升时，企业急于增加机器和厂房，于是投资猛增； 当需求只是保持在高位时，投资就回落。
Consumption and saving follow disposable income, wealth, interest rates and confidence.
消费和储蓄取决于可支配收入、财富、利率和信心。
Investment follows interest rates, expected profit, technology and confidence.
投资取决于利率、预期利润、技术和信心。
Now economic growth — a rise in real output — and two words you must keep apart.
现在讲经济增长——实际产出的上升——有两个词必须区分开。
Actual growth is the real rise in output that happens — the wavy line.
实际增长是真正发生的产出上升——就是那条波动的线。
Potential growth is the rise in what the economy can produce — the dashed trend.
潜在增长是经济生产能力的上升——就是那条虚线趋势。
The distance between them is the output gap.
两者之间的距离就是产出缺口。
Above the trend it is positive, and shortages push prices up.
在趋势之上，缺口为正，短缺推高物价。
Below it, negative: spare capacity and unemployment.
在趋势之下则为负：有闲置产能，也有失业。
So is growth always good?
那么增长总是好事吗？
Weigh both sides.
两面都要权衡。
The benefits are higher living standards, more jobs, and more tax revenue for schools and hospitals.
好处是：生活水平提高、就业增加、以及更多用于学校和医院的税收。
The costs are pollution, non-renewable resources used up, and gains that may reach only a few.
代价是：污染、不可再生资源被耗尽，以及收益可能只落到少数人手里。
So growth is a trade-off, never a free gift — and the examiner wants you to say so.
所以增长是一种取舍，绝不是白得的礼物——而考官希望你写出这一点。
That trade-off has a name.
这种取舍有一个名字。
Sustainable growth meets today's needs without harming the ability of future generations to meet theirs.
可持续增长是既满足今天的需要， 又不损害后代满足他们需要的能力。
Burn through the oil and the forests and tomorrow's economy is poorer.
把石油和森林耗尽，明天的经济就会更穷。
The wind these turbines use is never used up, so output can keep rising without stealing from the future.
这些风机所用的风永远不会被用完，所以产出可以继续增长，而不必偷走未来。
Fast growth that burns non-renewable resources and pollutes is what threatens sustainability.
而耗尽不可再生资源、造成污染的快速增长，正是可持续性受到的威胁。
Before you can cure unemployment you have to measure it.
在治理失业之前，你得先测量它。
The claimant count records everyone claiming unemployment benefit: quick and cheap, but it misses anyone out of work who does not claim.
申领救济人数统计所有申领失业救济的人：快而便宜， 但它漏掉了那些没有工作却不去申领的人。
The labour force survey asks a large sample who is working and who is looking for work.
劳动力调查向一大批样本询问谁在工作、谁在找工作。
It follows an international standard, so it is the wider measure, but it costs more and it is only a sample.
它遵循国际标准，所以是更宽的口径，但成本更高，而且它只是一个样本。
Four types, and the name matters.
四种类型，名称很重要。
Frictional unemployment is the short gap between one job and the next.
摩擦性失业是上一份工作与下一份工作之间的短暂空档。
Structural unemployment is when skills no longer match the jobs, as old industries decline.
结构性失业是技能不再与岗位匹配，因为旧产业在衰退。
Cyclical unemployment comes from weak demand in a recession.
周期性失业来自衰退中的需求不足。
Seasonal unemployment exists only at certain times of year.
季节性失业只在一年中某些时候才有。
Frictional plus structural gives the natural rate, which stronger demand cannot remove.
摩擦性加结构性就得到自然失业率，它无法靠加强需求来消除。
Now the link between jobs and prices.
现在看就业与物价之间的联系。
The Phillips curve plots inflation against unemployment.
菲利普斯曲线把通货膨胀对失业率作图。
In the short run it slopes downward, and that offers a choice.
在短期，它向下倾斜，这给了一个选择。
Push demand up and firms hire, so unemployment falls — but wages and prices are bid up, so inflation rises.
推高需求，企业就招人，失业下降——但工资和物价被抬高，通胀上升。
Lower unemployment is bought with higher inflation.
更低的失业是用更高的通胀换来的。
Does that trade-off last?
但这种取舍能持续吗？
Start at the natural rate, at point A.
从自然失业率出发，在 A 点。
The government boosts demand, and the economy moves along the short-run curve to point B: fewer people out of work, but higher inflation.
政府扩大需求，经济沿着短期曲线移动到 B 点：失业的人更少，但通胀更高。
Then workers notice.
然后工人们察觉了。
They expect higher prices, so they ask for higher wages, and the short-run curve shifts upward.
他们预期物价会更高，于是要求更高的工资， 短期曲线随之向上移动。
Unemployment slides back to the natural rate, at point C — same jobs, permanently higher inflation.
失业滑回到自然失业率，也就是 C 点—— 就业和原来一样，通胀却永久地更高了。
So in the long run the Phillips curve is vertical, and the trade-off is gone.
所以在长期，菲利普斯曲线是垂直的，取舍消失了。
Now money.
现在讲货币。
Money is anything widely accepted in payment, and it has four functions at once.
货币是任何被广泛接受用于支付的东西，它同时履行四项职能。
A medium of exchange, so nobody swaps chickens for shoes.
交换媒介，这样没人需要用鸡去换鞋。
A store of value, so you can save it.
价值储藏，这样你可以把它存起来。
A unit of account, one shared way to measure prices.
记账单位，一个共同的衡量物价的尺度。
And a standard of deferred payment, so people borrow now and repay later.
以及延期支付标准，这样人们可以先借后还。
Good money is also durable, portable, divisible and hard to fake.
好的货币还要耐用、便于携带、便于分割、难以伪造。
Two kinds of bank sit behind that money.
货币的背后有两类银行。
The central bank issues the notes, runs monetary policy and acts as lender of last resort.
中央银行发行纸币、执行货币政策， 并充当最后贷款人。
Commercial banks take deposits and lend most of them out, and because the loan is spent and deposited again, the banking system creates money.
商业银行吸收存款并把大部分贷出去，而由于贷款被花掉又被存回， 银行体系就创造了货币。
That brings moral hazard: a bank expecting to be rescued may take bigger risks, keeping the gains and passing on the losses.
这带来道德风险：一家预期会被救助的银行可能承担更大的风险， 把收益留给自己，把损失转嫁出去。
The central bank also holds the country's reserves.
中央银行还持有国家的储备。
Good money is limited in supply, not only durable and hard to fake.
好的货币供给要有限，不只是耐用和难以伪造。
If anyone can print as much as they like, money stops being a store of value.
如果任何人都可以随意印刷，货币就不再能储藏价值。
Why hold money at all?
为什么要持有货币？
Three motives.
三个动机。
Everyday payments — that is the transactions motive.
日常支付——这是交易动机。
A safety buffer for bad times — the precautionary motive.
为坏日子留的安全缓冲——预防动机。
And staying ready to buy assets when their price looks cheap — the speculative motive.
以及在资产价格看起来便宜时随时准备买入——投机动机。
Together they are liquidity preference, and they slope the demand for money downward.
合在一起就是流动性偏好，它使货币需求向下倾斜。
Finally, where does the interest rate come from?
最后，利率是怎么来的？
People hold money because it is liquid: it can be spent at once.
人们持有货币，是因为它有流动性：可以立刻花掉。
That is liquidity preference, and it makes the demand for money slope downward, because a high rate is the price of holding cash.
这就是流动性偏好，它使货币需求向下倾斜，因为高利率正是持有现金的代价。
The money supply is a vertical line, chosen by the central bank.
货币供给是一条垂直线，由中央银行决定。
Where they cross the rate is set — and watch it fall as more money arrives.
两者相交处利率就定下来了——看它随着更多货币进来而下降。
Three marks students throw away.
三个学生常丢的分。
First, the multiplier is one over one minus the propensity to consume, the same as one over the propensity to save.
第一，乘数等于一除以一减边际消费倾向， 也等于一除以边际储蓄倾向。
Keep the bracket.
括号别丢。
Second, a negative output gap is not negative growth; it means actual output sits below potential.
第二，负的产出缺口不等于负增长；它表示实际产出低于潜在产出。
Third, the long-run Phillips curve is vertical at the natural rate, so a permanent trade-off costs you the mark.
第三，长期菲利普斯曲线在自然失业率处是垂直的， 所以把取舍当成永久的，会让你丢分。
Get these three right, and Topic nine is yours.
把这三点做对，第九专题就是你的了。