Alevel/AP经济学A*学习笔记：通货膨胀的原因是什么？

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第6章：通货膨胀和货币政策——通货膨胀的原因是什么？

Demand-pull inflation需求拉动型通胀

Remember that Keynesians assume that the long run aggregate supply (LRAS) curve is horizontal, upward sloping and then vertical.

Assume that the current level of aggregate demand is AD1.

The price level is P1 and the level of real output is Y1. There is a lot of spare capacity in the economy.

The level of output is nowhere near the full employment level YFE.

An increase in aggregate demand (AD from now on) to AD2 in this situation, due to a rise in government spending, for example, will cause in increase in real output (to Y2) with no penalty in terms of rising prices.

请记住，凯恩斯主义者假设长期总供给（LRAS）曲线是水平的、向上倾斜的然后是垂直的。假设当前总需求水平为 AD 1。价格水平为 P 1，实际产出水平为 Y 1。经济中有大量闲置产能。产出水平远未接近充分就业水平 Y FE。例如，在这种情况下，由于政府支出的增加，总需求（从现在开始的 AD）增加到 AD 2将导致实际产出增加（到 Y 2），而不会因价格上涨而受到惩罚。

Further increases in government spending would start to be inflationary. A shift in the AD curve from AD2 to AD3 will increase real output (from Y2 to Y3) but the price level will also rise (from P1 to P2).

The result is similar if AD rises to AD4. At this stage, the economy is approaching the full employment level of real output, so some industries still have some spare capacity but others will be at full capacity, resulting in price rises in some industries, and so a rise in the average price level when AD rises.

政府支出的进一步增加将开始引发通胀。AD 曲线从 AD 2到 AD 3的移动会增加实际产出（从 Y 2到 Y 3），但价格水平也会上升（从 P 1到 P 2）。如果 AD 上升到 AD 4，结果是相似的。在这个阶段，经济正在接近实际产出的充分就业水平，因此一些行业仍有一些闲置产能，而另一些行业将处于满负荷状态，导致部分行业价格上涨，因此平均价格水平上升AD上升。

A further increase in AD when the economy is at full employment (AD level AD4) will simply result in a price rise with no increase in the level of real output.

当经济处于充分就业状态时（AD 水平 AD 4），AD 的进一步增加只会导致价格上涨，而实际产出水平不会增加。

The diagram shows that increases in the level of demand in an economy cause inflation. The rising level of demand is 'pulling' the price level up, hence the name 'demand-pull' inflation.

该图表明，经济中需求水平的增加会导致通货膨胀。需求水平的上升正在“拉动”价格水平，因此称为“需求拉动”通货膨胀。

This effect can also be shown on the 45-degree diagram, where a level of demand above that which gives a full employment equilibrium results in an inflationary gap.

这种影响也可以在 45 度图上显示，其中需求水平高于充分就业均衡的水平会导致通货膨胀缺口。

The best example of this happening in the UK economy was the consumer boom of the late 80s. Excessive demand in the economy forced the inflation rate up to 10%.

英国经济中发生这种情况的最好例子是 80 年代后期的消费热潮。经济中的过度需求迫使通货膨胀率高达 10%。

Cost-push inflation成本推动型通货膨胀

This cause of inflation is associated with rises in the costs of an industry, or the economy generally. The main reasons why costs might rise are

(i) increases in wages and salaries (the biggest cost of production economy wide);

(ii) increases in the cost of raw materials;

(iii) increases in the price of imported goods (either as finished goods, semi-finished manufactures or raw materials) due to a fall in the value of the £ or price rises in the country of origin;

(iv) increases in indirect taxes (or reductions in government subsidies). Any of these factors will have the following effect:

这种通货膨胀的原因与一个行业或整个经济的成本上升有关。成本可能上升的主要原因是（i）工资和薪水的增加（整个经济体的最大生产成本）；(ii) 原材料成本增加；(iii) 由于英镑价值下跌或原产国价格上涨，进口商品（制成品、半制成品或原材料）的价格上涨；(iv) 间接税增加（或政府补贴减少）。这些因素中的任何一个都会产生以下影响：

Short run aggregate supply (SRAS) curves have been used, but the analysis could be applied to LRAS curves. Quite simply, an increase in the costs of an economy will shift the SRAS curve to the left (from SRAS1 to SRAS2) causing the price level to rise to P2 and the level of real output to fall to Y2.

已使用短期总供给 (SRAS) 曲线，但该分析可应用于 LRAS 曲线。很简单，一个经济体成本的增加将使 SRAS 曲线向左移动（从 SRAS 1到 SRAS 2），导致价格水平上升到 P 2并且实际产出水平下降到 Y 2。

The oil price shocks of the mid 70s and early 80s are good examples of large increases in costs causing inflation.

The militant trade unions made things worse by insisting on above inflation pay rises to make up for the price rises plus any unpredictable future rises in the price level.

70 年代中期和 80 年代初的油价冲击是成本大幅增加导致通货膨胀的好例子。激进的工会坚持以高于通货膨胀的工资来弥补物价上涨以及任何不可预测的未来物价上涨，从而使事情变得更糟。

This brings us onto an important subsequent effect of cost-push inflation, namely, wage-price spirals.

During the price rises of the mid 70s, caused by the initial supply side shock of the huge rise in the price of oil, trade unions would press for higher wages.

They were powerful bodies in those days and usually got what they wanted. Firms were forced to raise their prices to maintain profit levels.

The loss in international competitiveness may well cause the £ to fall in value, increasing the price of imported goods.

These further increases in the price level caused more demands for higher wages from the trade unions. If successful, firms would raise their prices again, and so on.

The price level would spiral out of control.

这将我们带到了成本推动型通货膨胀的一个重要后续效应，即工资价格螺旋。在 70 年代中期的物价上涨期间，由于石油价格大幅上涨的初期供给侧冲击，工会会要求提高工资。在那些日子里，他们是强大的身体，通常会得到他们想要的东西。企业被迫提高价格以维持利润水平。国际竞争力的丧失很可能导致英镑贬值，从而提高进口商品的价格。物价水平的进一步上涨引起了工会对更高工资的更多要求。如果成功，公司将再次提高价格，依此类推。价格水平将失控。

The unions may well have been aware that continual increases in their wage were self defeating because the real value of these increases was quickly eroded by the subsequent rises in the price level, but which union was going to act sensibly first? Only if all unions stopped asking for more money would the spiral be broken.

工会很可能已经意识到，工资的持续增长是自取其辱，因为这些增长的实际价值很快被随后的物价水平上涨所侵蚀，但哪个工会会首先采取明智的行动呢？只有当所有工会都停止要求更多的钱时，螺旋才会被打破。

The effect was made worse by the 'leap-frogging' that took place. If the car workers got 15%, the miners wanted 17% and the steel workers wanted 20%.

The car workers would then go back to their employers and say, "the steel workers got 20%, so we want at least 20%."

发生的“跨越式”使效果变得更糟。如果汽车工人得到 15%，矿工想要 17%，钢铁工人想要 20%。然后，汽车工人会回到他们的雇主那里说，“钢铁工人得到了 20%，所以我们至少要 20%。”

The Quantity Theory of Money货币数量论

The last two causes of inflation were Keynesian explanations. As was said earlier, monetarists believed that sustained inflation would only occur if there was an increase in the money supply.

The 'Quantity Theory of Money' can be used to explain the monetarists' point of view.

通货膨胀的最后两个原因是凯恩斯主义的解释。如前所述，货币主义者认为，只有货币供应量增加，才会发生持续的通货膨胀。“货币数量论”可以用来解释货币主义者的观点。

The money supply (M) is the amount of money in the economy. There are lots of definitions as to what exactly constitutes money, but for the time being, let us assume that it includes only notes and coins.

货币供应量（M）是经济中的货币数量。关于货币的确切构成有很多定义，但暂时让我们假设它仅包括纸币和硬币。

The velocity of circulation (V) refers to how quickly this money 'circulates' around the economy. One ten pound note may get spent three times in one week. So M times V is, effectively, equal to the 'money spent' in an economy.

流通速度（V）是指货币在经济中“流通”的速度。一张 10 英镑的钞票可能会在一周内花费 3 次。因此，M 乘以 V 实际上等于一个经济体中的“花费”。

P is the price level and y is the level of real output, or real income (some textbooks will use 'T' for transactions), which ever you prefer. P times y, therefore, represents the value of everything on which money is spent.

P 是价格水平，y 是实际产出水平或实际收入水平（一些教科书将使用“T”进行交易），无论您喜欢哪个。因此，P 乘以 y 表示所花费的一切的价值。

It has to be true that MV = Py. Money spent = what the money is spent on. That is why there are three horizontal lines instead of the usual two (the equals sign).

This means that, rather than being an equation, this is an identity. Whatever is on the left (MV) always equals whatever is on the right (Py).

MV = Py 一定是真的。钱花=钱花在什么地方。这就是为什么有三条水平线而不是通常的两条（等号）。这意味着，这不是一个等式，而是一个恒等式。左边的东西（MV）总是等于右边的东西（Py）。

So far, this identity does not help us much. If, as the monetarists have done, one makes assumptions about certain variables in the identity, then things start to get interesting. Monetarists believe that V is fairly constant in the long run.

到目前为止，这个身份对我们帮助不大。如果像货币主义者所做的那样，对身份中的某些变量做出假设，那么事情就会开始变得有趣。货币主义者认为，从长远来看，V 是相当恒定的

They also claim that, whilst y is not constant, it does tend to grow at a predictable rate. The 'trend' growth rate in the UK is currently 2.5%. More particularly, monetarists believe that the long term 'trend' growth rate is determined by the position of the vertical long run aggregate supply curve which, in turn, is determined by supply side polices. They believe that y is exogenous, or determined outside this particular model.

他们还声称，虽然 y 不是恒定的，但它确实倾向于以可预测的速度增长。目前英国的“趋势”增长率为 2.5%。更具体地说，货币主义者认为，长期“趋势”增长率是由垂直的长期总供给曲线的位置决定的，而这又是由供给侧政策决定的。他们认为 y 是外生的，或者是在这个特定模型之外确定的。

Now the identity becomes a meaningful equation. If V is constant and y is at least predictable, then any significant change in M will cause a similar change in P. So large rises in the money supply (M) cause large rises in the price level (P).

现在身份变成了一个有意义的等式。如果 V 是常数并且 y 至少是可预测的，那么 M 的任何显着变化都会导致 P 发生类似的变化。因此，货币供应量 (M) 的大幅上升会导致价格水平 (P) 的大幅上升。

A fairly simple theory really. Of course, the Keynesians highlight many pitfalls. What if V is not constant? Good question.

Many economists think this may be why the Thatcher experiment of the early 80s did not work. She was very keen on this theory.

She tried to control the money supply through high interest rates and attempted control of government borrowing.

Not only did she have problems in controlling the money supply, but the theory just didn't seem to work.

When the money supply grew faster than she had planned, inflation still fell and when the money supply was finally under control, inflation started to rise again!

一个相当简单的理论。当然，凯恩斯主义者强调了许多陷阱。如果 V 不是常数怎么办？好问题。许多经济学家认为这可能是 80 年代初的撒切尔实验没有奏效的原因。她非常热衷于这个理论。她试图通过高利率来控制货币供应，并试图控制政府借贷。她不仅在控制货币供应方面存在问题，而且这个理论似乎也行不通。当货币供应量增长超过她的计划时，通货膨胀仍然下降，当货币供应量终于得到控制时，通货膨胀又开始上升！

When the percentage changes in M and P are relatively small (as they are in the UK), then any significant change in V will totally muck up this simple looking theory.

This theory works very well in countries that keep printing money in a desperate attempt to save the economy (like Russia).

If M is growing at, say, 100%, then changes in V and y will be so small in comparison that P is bound to rise substantially.

当 M 和 P 的百分比变化相对较小时（就像在英国一样），那么 V 的任何显着变化都会完全破坏这个简单的理论。这一理论在那些为了挽救经济而不断印钞的国家（如俄罗斯）非常有效。例如，如果 M 以 100% 的速度增长，那么 V 和 y 的变化将非常小，以至于 P 必然会大幅上升。

Other problems involved the time lags between changes in the money supply and price changes and, probably the most important point, does M affect P, or is it P that affects M?

其他问题涉及货币供应量变化和价格变化之间的时间滞后，可能最重要的一点是，M 会影响 P，还是 P 会影响 M？

Monetarists argued that the increase in M meant that consumers and businesses found that they had excess money balances, which would be spent (consumers) or invested (firms). This caused an increase in aggregate demand and inflation.

货币主义者认为 M 的增加意味着消费者和企业发现他们有多余的货币余额，这些余额将被花费（消费者）或投资（企业）。这导致总需求和通货膨胀的增加。

Keynesians argued that the rise in inflation was caused by factors in the real economy (demand-pull and cost-push).

The money supply would then expand to accommodate the increase in aggregate demand.

In other words, Keynesians believed the causal link was the other way round - increases in price (caused by the real economy) caused increases in the money supply and not that increases in the money supply caused increases in the price level.

凯恩斯主义者认为，通货膨胀的上升是由实体经济中的因素（需求拉动和成本推动）引起的。然后货币供应量将扩大以适应总需求的增加。换句话说，凯恩斯主义者认为因果关系是相反的——价格上涨（由实体经济引起）导致货币供应量增加，而不是货币供应量增加导致物价水平上涨。

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