Macroeconomic activity, objectives and policy
International Baccalaureate · IB Diploma · Economics · SL Topic 4 8:14 English narration · English + 中文 subtitles burned in
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In 2020 output fell faster than at any time since the 1930s, and central banks cut interest rates close to zero.
2020 年产出下降速度是 20 世纪 30 年代以来最快的，各国央行把利率降到接近零。
Two years later inflation reached a forty-year high, and the same banks raised rates quickly.
两年后通胀创下四十年新高，同样这些央行又迅速加息。
Macroeconomics explains why output, jobs and prices move together, and what policy can do.
宏观经济学解释产出、就业和物价为什么一起变动，以及政策能做什么。
Households sell land, labour, capital and enterprise to firms and earn incomes, which they spend on firms' goods.
家庭把土地、劳动、资本和企业家才能卖给企业，获得收入，再用收入购买企业的产品。
Some money leaks out as saving, taxes and imports. Some comes back in as investment, government spending and exports.
一部分钱以储蓄、税收和进口的形式漏出，一部分以投资、政府支出和出口的形式注入。
If injections are larger than leakages, national income grows.
如果注入大于漏出，国民收入就增长。
Gross domestic product is the value of all final goods and services produced in a year.
国内生产总值是一年内生产的全部最终产品和服务的价值。
You can add what each industry produces, add all incomes, or add all spending: C plus I plus G plus net exports.
可以把各行业的产出相加，也可以把所有收入相加，或者把所有支出相加：C + I + G + 净出口。
In principle all three give the same answer.
理论上三种方法结果相同。
Nominal GDP uses each year's prices; real GDP removes price changes, so it shows whether the country really produced more.
名义 GDP 用当年价格；实际 GDP 剔除了价格变化，能看出一个国家是否真的生产得更多。
Per capita figures divide by the population.
人均数字除以人口。
And purchasing power parity converts currencies at rates that buy the same basket, because a dollar buys more haircuts in Chengdu than in London.
购买力平价按能买到同一篮子商品的汇率换算，因为一美元在成都能理的发比在伦敦多。
GDP leaves out unpaid work at home and the informal economy. It says nothing about how income is shared, and it counts a polluting factory's output but not the damage.
GDP 不包括家务劳动和非正规经济，也不反映收入如何分配；它计入污染工厂的产出，却不计算污染的损害。
The Human Development Index combines income with health and education.
人类发展指数把收入与健康和教育结合起来。
Real GDP does not grow smoothly.
实际 GDP 并不平稳增长。
In a boom, output is above trend and inflation tends to rise.
繁荣时产出高于趋势，通胀往往上升。
In a recession, output falls and unemployment rises.
衰退时产出下降，失业上升。
At the slump, output is furthest below trend.
萧条时产出离趋势最远。
Then comes the recovery, and the cycle repeats around the trend.
然后是复苏，周期围绕趋势不断重复。
Aggregate demand is total planned spending: consumption, investment, government spending and net exports.
总需求是计划总支出：消费、投资、政府支出和净出口。
It slopes down, because a higher price level makes money worth less and exports dearer.
它向下倾斜，因为物价水平越高，货币越不值钱，出口越贵。
A change in the price level moves along the curve; a change in any part shifts it.
物价水平变化是沿曲线移动；任何组成部分的变化都会使曲线移动。
Short-run aggregate supply slopes up and shifts when costs change.
短期总供给向上倾斜，成本变化时会移动。
In the long run, monetarists draw a vertical line at potential output: wages adjust, and the economy returns to full employment by itself.
长期来看，货币主义者画一条位于潜在产出的垂直线：工资会调整，经济自己回到充分就业。
Keynesians say it can stay stuck below full employment, with flat supply while there is spare capacity.
凯恩斯主义者认为经济可能长期低于充分就业，有闲置产能时供给曲线是平的。
Aggregate demand meets short-run supply at an output of seventy and a price level of fifty-five.
总需求与短期总供给相交于产出 70、物价水平 55。
Full employment is eighty, so there is a recessionary gap of ten, with cyclical unemployment.
充分就业产出是 80，所以有 10 的衰退性缺口，伴随周期性失业。
If demand rises, the new equilibrium is eighty-five at sixty-two point five: an inflationary gap of five.
如果需求增加，新均衡在 85、62.5：这是 5 的通胀性缺口。
In the monetarist view, a recessionary gap closes by itself: unemployed workers accept lower wages, supply shifts right and output returns to eighty.
货币主义观点认为衰退性缺口会自行消除：失业工人接受更低的工资，供给右移，产出回到 80。
Keynesians reply that wages rarely fall, so a recession can last for years unless the government acts.
凯恩斯主义者回应说，工资很少下降，所以除非政府行动，衰退可能持续多年。
Someone is unemployed if they are of working age, have no job and are actively looking.
处于工作年龄、没有工作并积极找工作的人就是失业者。
There are four types: cyclical, when demand falls; structural, when skills no longer match the jobs; frictional, between jobs; and seasonal.
失业有四种：需求下降引起的周期性失业；技能与岗位不匹配的结构性失业；换工作期间的摩擦性失业；以及季节性失业。
With no cyclical unemployment, the economy is at its natural rate.
没有周期性失业时，经济处于自然失业率。
Demand-pull inflation comes when demand grows faster than the economy can produce.
需求拉动型通胀发生在需求增长快于经济生产能力时。
Cost-push inflation comes when firms' costs rise and supply shifts left, so prices rise while output falls.
成本推动型通胀发生在企业成本上升、供给左移时，物价上涨而产出下降。
High inflation hurts savers; deflation makes people delay spending.
高通胀伤害储蓄者；通缩让人们推迟消费。
Most central banks aim for about two per cent.
多数央行把目标定在 2% 左右。
Growth is a rise in real GDP.
经济增长是实际 GDP 的增加。
In the short run it can come from more demand using spare capacity. In the long run it needs more or better factors of production.
短期可以来自需求增加、利用闲置产能；长期需要更多或更好的生产要素。
Growth raises incomes but can harm the environment, so the goal is sustainable growth.
增长提高收入，但可能破坏环境，所以目标是可持续增长。
The Lorenz curve plots the income share of the poorest twenty per cent, forty per cent and so on.
洛伦兹曲线画出最穷的 20%、40% 等人群所得收入的比例。
The straight line is perfect equality.
直线代表完全平等。
Here the poorest fifth earns five per cent, and the curve sags below the line.
这里最穷的五分之一只得到 5% 的收入，曲线向下弯离直线。
The Gini coefficient is the gap, area A, over the whole triangle: zero point four.
基尼系数是两者之间的面积 A 除以整个三角形：0.40。
Absolute poverty means too little to buy basic needs: the World Bank's line is three dollars a day.
绝对贫困指收入不足以购买基本必需品：世界银行的标准是每天 3 美元。
Relative poverty means far below others in the same country, often under half or sixty per cent of the median.
相对贫困指远低于本国其他人，通常低于中位数收入的 50% 或 60%。
The multidimensional index also counts health, education and things like clean water.
多维贫困指数还计算健康、教育以及清洁用水等生活条件。
Governments use progressive taxes, where richer people pay a higher share; transfer payments such as pensions and benefits; spending on education and health; and minimum wages.
政府使用累进税，让富人承担更高的比例；发放养老金和福利等转移支付；投入教育和医疗；规定最低工资。
But high tax rates and generous benefits can weaken incentives: the trade-off between equity and efficiency.
但高税率和慷慨的福利可能削弱激励：这就是公平与效率之间的权衡。
The central bank sets the policy interest rate, buys or sells government bonds, and sets the share of deposits banks must keep.
中央银行设定政策利率，买卖政府债券，规定银行必须保留的存款比例。
When rates are already near zero, it uses quantitative easing.
利率已接近零时，就采用量化宽松。
Remember the real rate: a loan at five per cent with three per cent inflation costs only two.
记住实际利率：利率 5%、通胀 3% 时，贷款的实际成本只有 2%。
The interest rate is the price of money.
利率是货币的价格。
The central bank sets the money supply, a vertical line.
中央银行决定货币供给，是一条垂直线。
Demand for money slopes down, because holding cash means giving up interest.
货币需求向下倾斜，因为持有现金就放弃了利息。
When the bank shifts supply right, the interest rate falls from five per cent to three.
当央行把供给右移时，利率从 5% 降到 3%。
When the central bank raises rates, borrowing costs more, so households buy fewer homes and cars and firms invest less.
央行加息后，借款更贵，家庭少买房买车，企业减少投资。
Saving becomes more attractive.
储蓄更有吸引力。
Money flows in from abroad, the currency rises and net exports fall.
外国资金流入，本币升值，净出口下降。
Aggregate demand shifts left.
总需求左移。
Central banks can act quickly, move in small steps, and are independent of politics.
中央银行行动快，可以小步调整，而且独立于政治。
But the full effect takes eighteen months or more, and in a deep recession low confidence means people will not borrow even at very low rates.
但完全见效需要十八个月以上；在严重衰退中，信心低迷，即使利率很低人们也不愿借钱。
Fiscal policy uses government spending and taxes.
财政政策运用政府支出和税收。
Revenue comes from direct taxes on income and profits, and indirect taxes such as VAT.
收入来自对收入和利润征收的直接税，以及增值税等间接税。
Spending is current, like teachers' wages, capital, like railways, or transfers, like pensions.
支出分为经常性支出，如教师工资；资本性支出，如铁路；以及转移支付，如养老金。
Raising spending or cutting taxes shifts demand right.
增加支出或减税会使需求右移。
Automatic stabilisers need no new decision.
自动稳定器不需要新的决策。
In a recession, tax revenue falls and benefit spending rises by itself, which supports demand.
衰退时税收自动减少，福利支出自动增加，从而支撑需求。
In a boom the opposite happens, and demand is held back.
繁荣时情况相反，需求受到抑制。
Fiscal policy can be aimed at particular regions or groups, and it works in a deep recession.
财政政策可以针对特定地区或群体，在严重衰退中也有效。
But government borrowing may raise interest rates and crowd out private investment, projects take a long time, and debt rises.
但政府借款可能推高利率、挤出私人投资，项目耗时长，债务也会上升。
Supply-side policies raise the economy's capacity.
供给侧政策提高经济的生产能力。
Here long-run supply shifts from eighty-five to a hundred and five along a fixed demand curve.
这里长期总供给沿着不变的需求曲线从 85 移到 105。
Real GDP rises by twenty and the price level falls from forty-seven point five to thirty-seven point five: growth without inflation.
实际 GDP 增加 20，物价水平从47.5 降到 37.5：没有通胀的增长。
Interventionist policies have the government act: education, healthcare, roads and broadband, research grants.
干预型政策由政府出手：教育、医疗、道路和宽带、研发补助。
Market-based policies let markets work more freely: lower taxes, flexible labour laws, deregulation and privatisation.
市场导向型政策让市场更自由地运作：降低税率、灵活的劳动法、放松管制和私有化。
Most take years, and some widen inequality.
多数需要数年才见效，有些还会扩大不平等。
To finish: measure output three ways and in real terms; find the equilibrium where demand meets supply and compare it with full employment; know the objectives; and match each policy to the curve it moves.
总结：用三种方法、按实际值衡量产出；找到需求与供给的均衡点，并与充分就业比较；掌握各项目标；把每种政策与它移动的曲线对应起来。