实际汇率是有效汇率吗(实际汇率大于1说明什么)

A-level economics revision guides and question banks covering labour markets, supply and demand, market structure and all core economics a-level topics.

以下内容我们会持续更新：

今天带给大家Alevel经济笔记是：第4章：Exchange Rates—

What is an Exchange Rate?

The Real Exchange Rate；

What is an Exchange Rate?

If you asked the ‘Average Joe’ what the exchange rate is, he would probably tell you “it’s the amount of dollars (or euros, for example) you get to the pound”.

Whilst not the perfect definition, he is technically correct.

Of course, most people only need to understand exchanges rates when they go on holiday. As an economist, you need to understand how they affect the balance of payments, the inflation rateand many other important macroeconomicobjectives.

如果您问“平均乔”汇率是多少，他可能会告诉您“这是您兑换英镑的美元（或欧元）数量”。虽然不是完美的定义，但他在技术上是正确的。当然，大多数人只需要在度假时了解汇率。作为经济学家，您需要了解它们如何影响国际收支、通货膨胀率和许多其他重要的宏观经济目标。

Unfortunately, our layman’s definition of the exchange rate is not the only one.

In this Learn It, we shall look at the different definitions of the exchange rate before we go on to investigate more important issues like how this exchange rate is determined.

不幸的是，我们外行对汇率的定义并不是唯一的。在本次学习中，我们将先了解汇率的不同定义，然后再继续研究更重要的问题，例如如何确定汇率。

The layman’s exchange rate外行的汇率

This is the definition that most people understand when discussing the exchange rate. It is often referred to as the nominal exchange rate.

This is defined as the rate at which one currency can be converted, or ‘exchanged’, into another currency.

这是大多数人在讨论汇率时所理解的定义。它通常被称为名义汇率。这被定义为一种货币可以转换或“兑换”成另一种货币的比率。

The pound is currently worth about one and a half US dollars.

One pound can be converted into one and a half dollars. This, therefore, is the exchange rate between the pound and the dollar.

The table below gives you some of the exchange rates against the pound over the last 20 years:

英镑目前大约值一美元半。一英镑可以兑换成一美元半。因此，这就是英镑和美元之间的汇率。下表为您提供了过去 20 年对英镑的一些汇率：

* The exchange rate of the euro is based on the market rate on the 23rd August 2000.

The rates for the German mark and French franc are based on their respective rates against the euro as of 1st January 1999 (which haven’t changed) multiplied by the pound/euro exchange rate on the 23rd August 2000.

* 欧元汇率基于 2000 年 8 月 23 日的市场汇率。德国马克和法国法郎的汇率基于 1999 年 1 月 1日各自对欧元的汇率（没有变化) 乘以 2000 年 8 月23日的英镑/欧元汇率。

The figures for the euro only began in 1995. Pre-1999, these figures represent an average of the 11 countries that eventually joined the single currency.

欧元的数据始于 1995 年。1999 年之前，这些数据代表了最终加入单一货币的 11 个国家的平均值。

As you can see, the pound was particularly strong in the early 80s, due to the effects of being a net exporter of oil for the first time.

It was weak in the few years after the UK fell out of the Exchange Rate Mechanism (ERM), and then rose again from the summer of 1996 to its current high levels.

There will be much discussion of the reasons for these changes in later Learn-Its.

如您所见，由于首次成为石油净出口国的影响，英镑在 80 年代初特别坚挺。在英国退出汇率机制 (ERM)后的几年里，它表现疲软，然后从 1996 年夏天再次上升到目前的高位。在以后的 Learn-Its 中将有很多关于这些变化的原因的讨论。

The trade weighted index 贸易加权指数

The formal name for this measure of the exchange rate is the effective exchange rate.

Most newspapers prefer to use the name ‘trade weighted index’, probably because it is a better description of the exchange rate itself.

这种衡量汇率的正式名称是有效汇率。大多数报纸更喜欢使用“贸易加权指数”这个名称，可能是因为它更好地描述了汇率本身。

This measure is an index series. The ‘numbers’ published have no units and the series is based on a base year, which is currently 1990 (although it could be any year).

Changes in this ‘number’ can be used to measure percentage changes in the statistic on which the index series is based (in this case, the value of the pound).

Like the Retail Price Index (RPI), which tries to reflect the average price level in the UK across thousands of goods and services, the trade weighted index is trying to give an idea of the average exchange rate across all the important currencies.

The weights in the average reflect the fact that the UK does more trade with some countries than others (just like the weights in the RPI reflect the fact that some goods and services are more important than others).

这个措施是一个指数系列。公布的“数字”没有单位，该系列基于基准年，目前是 1990 年（尽管可能是任何年份）。这个“数字”的变化可以用来衡量指数系列所依据的统计数据的百分比变化（在这种情况下，是英镑的价值）。与试图反映英国数千种商品和服务的平均价格水平的零售价格指数 (RPI)一样，贸易加权指数试图给出所有重要货币的平均汇率的概念。平均值中的权重反映了英国与某些国家的贸易比其他国家更多的事实（就像 RPI 中的权重反映了某些商品和服务比其他国家更重要的事实一样）。

The example below should help to explain. Assume that the UK only trade with three countries – the USA, France and Ireland.

The table below shows how the nominalexchange rates have changed, but that the value of the weighted average depends on the importance of the countries in trading terms with the UK.

下面的例子应该有助于解释。假设英国只与三个国家进行贸易——美国、法国和爱尔兰。下表显示了名义汇率如何变化，但加权平均值的值取决于各国在与英国的贸易条件中的重要性。

It should be noted that these exchange rates are not totally accurate. They were picked to make the arithmetic easy, as you will see.

应该注意的是，这些汇率并不完全准确。正如您将看到的，它们被选中是为了使算术变得简单。

In the example above, we can see that the pound rose fairly robustly against the dollar and franc over the year, but the pound fell drastically against the Irish punt.

If we took a non-weighted, normal average, we would find that the pound fell overall against these three currencies:

在上面的例子中，我们可以看到英镑兑美元和法郎在这一年里上涨得相当强劲，但英镑兑爱尔兰平底船则大幅下跌。如果我们采用非加权正常平均值，我们会发现英镑兑这三种货币整体下跌：

In other words, each country has a weight of 33%. So, another way of working this out is the following:

也就是说，每个国家的权重都是33%。因此，解决此问题的另一种方法如下：

What has happened here is that the large fall in the pound’s exchange rate against the punt (the least important currency in terms of trade – hence the 10% weight) has outweighed the significant rise in the pound against the more important currencies (in terms of trade).

This is why weights are used to reflect this importance. Look at the weighted average below:

这里发生的情况是，英镑兑平底船（在贸易方面最不重要的货币 – 因此权重为 10%）的大幅下跌超过了英镑兑更重要的货币（以贸易）。这就是为什么使用权重来反映这种重要性。看看下面的加权平均值：

In the example that has been constructed, if we assume that the base year is 1998, which is then given the ‘number’ 100, the ‘number’ given to the year 1999 is 106, because the weighted average has risen by 6%.

在已经构建的示例中，如果我们假设基准年是 1998 年，那么给定“数字”100，那么赋予 1999 年的“数字”是 106，因为加权平均值上升了 6%。

The overall rise in this ‘trade weighted index’ reflects the fact that the pound rose against the currencies that made up 90% of the ‘importance’ of this measure.

这一“贸易加权指数”的总体上升反映了英镑兑构成该指标“重要性”的 90% 的货币上涨的事实。

The diagram below shows what has happened to the realtrade weighted index over the last 20 years:

下图显示了过去 20 年实际贸易加权指数的变化：

This graph is only a sketch and uses the figures for yearly averages, but you still get a feel for the trends in the effective exchange rate over the last 20 years.

It should be noted that, just like the RPI, the weights for this exchange rate do change over time.

In the 70s, the weight for the USA was about a third, and the combined weight for the 15 EU countries was slightly more.

The UK now trades much more with the EU than the USA.

The weight for the USA is now nearer one-sixth and the weight for the 15 EU countries is about three-quarters!

该图只是一个草图，并使用这些数字作为年度平均值，但您仍然可以了解过去 20 年有效汇率的趋势。应该注意的是，就像 RPI 一样，该汇率的权重确实会随着时间而变化。在 70 年代，美国的权重约为三分之一，而 15 个欧盟国家的权重加起来略多一些。英国现在与欧盟的贸易比美国多得多。美国的重量现在接近六分之一，欧盟 15 个国家的重量约为四分之三！

It is of no surprise, therefore, that the trade weighted index measure of the pound tends to follow the pound’s course with the euro rather than the dollar.

The pound has lost around 8% of its value against the dollar over the last year. The pound has risen about 9% against the euro in the same time.

The trade-weighted index has risen by about 4% over the year, showing that the influence of the euro is stronger than that of the dollar.

因此，英镑的贸易加权指数衡量指标倾向于跟随欧元而不是美元跟随英镑走势也就不足为奇了。去年，英镑兑美元贬值了约 8%。与此同时，英镑兑欧元上涨了约 9%。贸易加权指数全年上涨约4%，显示欧元的影响力强于美元。

The Real Exchange Rate

If you put 100 pounds in a bank, and earn 8% interest over the year (eight pounds interest), this is only the nominalrate of interest.

What you really get – the realrate of interest – depends on the rate of inflation as well.

If inflation was running at 5% over the year, then the real rate of interest was only 3% (8% − 5%).

Your 100 pounds became 108 pounds, but goods and services costing 100 pounds a year ago now cost 105 pounds. In realterms you have only really made 3 pounds.

如果你把 100 英镑存入银行，一年赚取 8% 的利息（8 英镑利息），这只是名义利率。你真正得到的——实际利率——也取决于通货膨胀率。如果全年通货膨胀率为 5%，那么实际利率仅为 3%（8% – 5%）。你的 100 英镑变成了 108 英镑，但一年前价值 100 英镑的商品和服务现在价值 105 英镑。实际上，您实际上只赚了 3 磅。

The nominalexchange rate between, say, the pound and the dollar is simply the amount of dollars you can buy for each pound as dictated by the price in the foreign exchange markets.

To find the realexchange rate, we have to allow for relative inflation rates in the two countries, just as you do with interest rates, of growth, or spending, or incomes or anything where the price rises distort the picture.

例如，英镑和美元之间的名义汇率就是外汇市场价格决定的每英镑可以购买的美元数量。为了找到实际汇率，我们必须考虑两国的相对通货膨胀率，就像你计算利率、增长、支出、收入或任何价格上涨扭曲了画面的东西一样。

In this case, the picture that is being distorted is the UK’s competitiveness, in terms if trade, with other countries.

If the trade weighted index for sterling fell by, say, 5% over a given year, this would make UK manufacturers’ exports 5% cheaper in foreign countries.

If sterling falls, UK manufacturers are happy!

But if, over the same period of time, prices in the UK rose by 5%, the benefit in terms of the reduced value of the pound for UK manufacturers would be cancelled out by the higher domestic prices.

在这种情况下，被扭曲的画面是英国在贸易方面与其他国家的竞争力。如果英镑的贸易加权指数在某一年下降 5%，这将使英国制造商的出口商品在国外便宜 5%。如果英镑下跌，英国制造商会很高兴！但是，如果在同一时期，英国的价格上涨了 5%，那么英国制造商的英镑贬值带来的好处将被国内价格的上涨所抵消。

The real exchange rate tries to take relative changes in countries’ inflation rates into account.Look at the formula below:

实际汇率试图将各国通货膨胀率的相对变化考虑在内。看下面的公式：

In this formula, the ‘world’ price level is an average of the price levels of the sixteen countries that are included in the trade weighted effective exchange rate.

Assume that the UK’s effective exchange rate stays constant over a given year.

If UK inflation is 10% over that year, and world inflation is only 7%, then the realexchange rate will rise by roughly 3% (10% − 7%).

The exact rise would be 2.8%.

See if you can work out why it is not exactly 3%. Read through the following example, trying to understand the principles,click to reveal answer when you have finished.

在这个公式中，“世界”价格水平是贸易加权有效汇率中包含的 16 个国家的价格水平的平均值。假设英国的有效汇率在某一年保持不变。如果当年英国通货膨胀率为 10%，而世界通货膨胀率仅为 7%，那么实际汇率将上涨大约 3%（10% – 7%）。确切的涨幅为 2.8%。看看你能不能弄清楚为什么它不完全是 3%。通读下面的例子，试着理解原理，完成后点击显示答案。

Assume that the RPI in the UK is 100 and the RPI for the rest of the world also happens to be 100. Hence:

假设英国的 RPI 是 100，而世界其他地区的 RPI 也恰好是 100。因此：

In the example above, we said that UK inflation was 10% over the given year.

This gives a new RPI of 110.

In the same way, the new RPI for the rest of the world will be 107. So the new ratio of price levels will be:

在上面的例子中，我们说英国在给定年份的通货膨胀率为 10%。这给出了 110 的新 RPI。同样，世界其他地区的新 RPI 将是 107。所以新的价格水平比率将是：

So the ratio has risen by 0.028. As a percentage (multiplying by 100) this is 2.8%.

所以这个比率上升了0.028。百分比（乘以 100）为 2.8%。

The problem for the UK during the 70s and 80s was that, regardless of how low the effective exchange rate was, its inflation rate tended to be higher than the world average.

This caused the real exchange rate to rise (for a given effective exchange rate), making UK exports relatively more expensive abroad and so less competitive pricewise.

For a detailed discussion on the competitiveness of UK industry, see the topic called ‘Why trade?‘

英国在 70 年代和 80 年代面临的问题是，无论有效汇率有多低，其通货膨胀率往往高于世界平均水平。这导致实际汇率上升（对于给定的有效汇率），使英国出口在国外相对昂贵，因此价格竞争力下降。有关英国工业竞争力的详细讨论，请参阅题为“为什么要贸易？‘

Purchasing Power Parity (PPP)购买力平价 (PPP)

This is not an official measure of the exchange rate, but is often used to assess at what level the exchange rate ought to be.

PPP gives a ‘parity’, or exchange rate, based on the prices of a given basket of goods and services in two different countries.

这不是汇率的官方衡量标准，但通常用于评估汇率应该处于什么水平。购买力平价根据两个不同国家的给定一揽子商品和服务的价格给出“平价”或汇率。

For example, let us assume that this basket of goods and services contained the price of a bottle of lager, a pound of cheddar cheese, a litre of petrol and a visit to the cinema.

Look at the table below.

例如，让我们假设这一篮子商品和服务包含一瓶啤酒、一磅切达干酪、一升汽油和一次电影院的价格。请看下表。

The four items in question cost £10 in the UK. The same items cost $14 in the USA and 105 francs in France.

So if the exchange rate between the UK and the USA was based on the price of these four goods and services, it would be £1 = $1.40.

The PPP between the UK and France would be £1 = 10.50 francs.

有问题的四件物品在英国的售价为 10 英镑。同样的物品在美国售价 14 美元，在法国售价 105 法郎。因此，如果英国和美国之间的汇率基于这四种商品和服务的价格，那么它将是 1 英镑 = 1.40 美元。英国和法国之间的购买力平价为 1 英镑 = 10.50 法郎。

It is often felt that the actual market exchange rates should match these PPPs as closely as possible.

The pound is felt to be overvalued at the moment by around 10% against the euro.

Paris always used to be the most expensive European city in which to spend a weekend. This dubious honour now belongs to London.

人们经常认为实际市场汇率应尽可能与这些 PPP 相匹配。英镑兑欧元目前被认为被高估了约 10%。巴黎曾经是欧洲周末最昂贵的城市。这个可疑的荣誉现在属于伦敦。