The Case for Free Trade - Comparative Advantage

自由贸易的案例--比较优势

「国际教育」A-level经济A*高分笔记：自由贸易的理由 - 绝对优势 In the numerical example in the last time, it was fairly obvious what the two countries should do. One was better at making wine, the other was better at making beer, so they each specialised, overall production rose and they were both better off after trading.

在上次的数字例子中，两个国家应该做什么是相当明显的。一个国家更擅长制造葡萄酒，另一个国家更擅长制造啤酒，所以他们各自专业化，整体产量上升，交易后他们的生活都会更好。

What should happen, though, if one of the two countries is best at making both the goods in question?

但是，如果这两个国家中的一个最擅长制造这两种商品，应该怎么办呢？

The 'pre-specialisation' situation 专业化前的情况

Assume that two countries, Germany and France, with similar amounts of resources (which is more or less true in the real world) both produce only two goods, wine and cheese (not so true in the real world!). The table below gives the production possibilities for a given year assuming that they each split their resources evenly between the production of wine and cheese.

假设两个国家，德国和法国，拥有相似的资源量（这在现实世界中或多或少是真实的），都只生产两种商品，葡萄酒和奶酪（在现实世界中并不那么真实！）。下表给出了某一年的生产可能性，假设他们各自在葡萄酒和奶酪的生产中平均分配资源。

Wine

Cheese

(Millions of bottles)

(Millions of kilos)

Germany

150

100

France

200

200

Total

350

300

In this example, where we assume that both countries produce only wine and cheese, France has an absolute advantage in the production of both wine and cheese. It is better at making both goods. Here are the relevant PPFs.

在这个例子中，我们假设两个国家都只生产葡萄酒和奶酪，法国在葡萄酒和奶酪的生产上都有绝对优势。它更擅长生产这两种商品。下面是相关的PPFs。

As you can see, France's PPF is further to the right than Germany's. They are better at making both goods, so why bother trade with Germany?

正如你所看到的，法国的PPF比德国的更靠右。他们更擅长制造这两种商品，那么为什么还要和德国进行贸易呢？

This is where the theory of comparative advantage comes in. This theory states that in the situation above, both countries can still benefit from specialisation and trade. Germany must specialise in the good at which it is 'least bad' at making, and France should specialise in the product at which it is best (or 'most good') at making. We find out who should specialise in what by finding, for each country, the opportunity cost of making each good in terms of the other good. This is where the PPFs come in handy. It is easier to see what the opportunity costs are using a diagram.

这就是比较优势理论的作用。该理论指出，在上述情况下，两个国家仍然可以从专业化和贸易中受益。德国必须专注于它 "最不差 "的产品，而法国应该专注于它最擅长（或 "最优秀"）的产品。我们通过找出每个国家生产每种产品的机会成本，来确定谁应该专门生产什么。这就是PPFs的用武之地。使用图表更容易看出机会成本是什么。

Finding the value of the opportunity costs 寻找机会成本的价值

Let's look at France first. France is initially at point A on its PPF, producing 200 million bottles of wine (from now on, W) and 200 million kilograms of cheese (from now on, C). If France was to make one more kilogram of cheese, you can see from the diagram that a bottle of wine would have to be sacrificed. So the opportunity cost of making 1C is 1W. If France were to make one more bottle of wine, it would have to sacrifice a kilogram of cheese. The opportunity cost of making 1W is 1C. The gradient of the PPF (which is -1) determines the size of the opportunity cost.

我们先来看看法国。法国最初处于其PPF的A点，生产2亿瓶葡萄酒（从现在起，W）和2亿公斤奶酪（从现在起，C）。如果法国要多生产一公斤奶酪，从图中可以看出，必须要牺牲一瓶葡萄酒。所以生产1C的机会成本是1W。如果法国要多生产一瓶葡萄酒，就必须牺牲一公斤的奶酪。制造1W的机会成本是1C。PPF的梯度（为-1）决定了机会成本的大小。

The calculation is a little more complicated for Germany, currently at point B on its PPF. To make one more kilogram of cheese you can see from the steeper slope of the PPF that Germany will have to give up more than one bottle of wine. To be exact, the opportunity cost of 1C is 1½W. Again the gradient of the PPF (which is -1½) holds the key. To make one more bottle of wine, you can see that Germany will be giving up less than one kilogram of cheese. To be exact, the opportunity cost of 1W is 2C/3.

对德国来说，计算要复杂一些，因为它目前处于PPF的B点。为了多生产一公斤奶酪，你可以从PPF的陡峭坡度上看到，德国将不得不放弃超过一瓶葡萄酒。确切地说，1C的机会成本是1½W。PPF的坡度（为-1½）再次成为关键。为了多生产一瓶葡萄酒，你可以看到德国将放弃不到一公斤的奶酪。确切地说，1W的机会成本是2C/3。

The table above has been reproduced below, but the opportunity costs of making an extra unit of each product has been added in the relevant boxes.

上面的表格已经复制到下面，但每个产品多生产一个单位的机会成本已经被添加到相关的方框中。

Wine

Cheese

(Millions of bottles)

(Millions of kilos)

Germany

150

100

(1W costs C)

(1C costs 1W)

France

200

200

(1W costs C)

(1C costs 1W)

Total

350

300

Now that we have the opportunity costs of production, we can see which country is relatively better at making each good. In other words, we can see which country has a comparative advantage in producing which good. Let's look at wine first. France can make 1W at a cost of 1C, but Germany can make wine relatively more cheaply. It can make 1W for only 2C/3. Germany has a comparative advantage in the production of wine. With cheese, France can make 1C at a cost of 1W, but it is more costly in Germany, where 1C costs 1½W. France has a comparative advantage in the production of cheese.

现在我们有了生产的机会成本，我们可以看到哪个国家在生产每种商品方面相对更好。换句话说，我们可以看到哪个国家在生产哪种商品方面具有比较优势。让我们先看一下葡萄酒。法国可以用1C的成本制造1W的葡萄酒，但德国可以用相对更便宜的价格制造葡萄酒。它可以用2C/3的价格制造1W。德国在生产葡萄酒方面具有比较优势。对于奶酪，法国可以用1W的成本制造1C，但德国的成本更高，1C的成本为1½W。法国在奶酪的生产方面具有比较优势。

The situation after specialisation 专业化后的情况

So, Germany will specialise in wine and France will specialise in cheese. This gives the following table 因此，德国将专门生产葡萄酒，法国将专门生产奶酪。这就有了下面的表格 :

Wine

Cheese

(millions of bottles)

(millions of kilos)

Germany

300

0

France

0

400

Total

300

400

Notice that, although overall production has risen (700 units is bigger than 650 units), the extra 100 million kilograms of cheese have been produced with a loss of 50 million bottles of wine. This may seem like a bad deal if you particularly like wine! It is for this reason that the two countries in this situation are unlikely to specialise 100% in the product for which they have a comparative advantage. The table below gives a more sensible degree of specialisation which results in higher overall production of both goods.

请注意，虽然总体产量增加了（700个单位比650个单位大），但多生产的1亿公斤奶酪却损失了5000万瓶葡萄酒。如果你特别喜欢葡萄酒，这似乎是一个糟糕的交易! 正是由于这个原因，这种情况下的两个国家不太可能100%地专门生产他们具有比较优势的产品。下表给出了一个更合理的专业化程度，它能使两种商品的总产量提高。

Wine

Cheese

(millions of bottles)

(millions of kilos)

Germany

300

0

France

70

330

Total

370

330

Both wine and cheese lovers should be happy now! The two countries together now produce 20 million more bottles of wine and 30 million more kilograms of cheese. So now its time to trade. What will the terms of trade be?

葡萄酒和奶酪爱好者现在都应该感到高兴! 两国现在共同生产的葡萄酒增加了2000万瓶，奶酪增加了3000万公斤。因此，现在是进行贸易的时候了。贸易条件将是什么？

If France was still a closed economy, it could produce an extra kilogram of cheese at the cost of exactly one bottle of wine. Hence, France will not want to trade a kilogram of cheese for anything less than one bottle of wine. The domestic trade off is one kilogram of cheese for one bottle of wine, so France would hope to do better than that.

如果法国仍然是一个封闭的经济体，它可以多生产一公斤的奶酪，而代价恰恰是一瓶葡萄酒。因此，法国不会想用一公斤奶酪换取少于一瓶葡萄酒的东西。国内的交易是一公斤奶酪换一瓶葡萄酒，所以法国希望做得比这更好。

Similarly, if Germany was still a closed economy, it could produce an extra bottle of wine at the cost of only two-thirds of a kilogram of cheese. Germany would hope to get at least two-thirds of a kilogram of cheese for each bottle of wine that it trades with France. 1W for 2C/3 is the same as 1C for 1½W.

同样，如果德国仍然是一个封闭的经济体，它可以多生产一瓶葡萄酒，而成本只有一公斤奶酪的2/3。德国希望与法国交易的每瓶葡萄酒至少能得到三分之二的奶酪。1W换2C/3与1C换1½W是一样的。

So the 'price' will be somewhere between 1C for 1W and 1C for 1½W. France would rather the price was as close as possible to 1C for 1½W and Germany will hope that the price is as close as possible to 1C for 1W.

因此，"价格 "将介于1C换1W和1C换1½W之间。法国希望价格尽可能接近1C换1½W，而德国则希望价格尽可能接近1C换1W。

Let's say that the two countries agree on a price of 1C for 1¼W, and decide to trade 112 million kilograms of cheese for 140 million bottles of wine.

假设两国同意1C换1/4W的价格，并决定用1.12亿公斤奶酪换1.4亿瓶葡萄酒。

The situation after specialisation and trading 专业化和交易后的情况

The final, post-trade, table will look like this 最后，交易后的表格会是这样的 :

Wine

Cheese

(millions of bottles)

(millions of kilos)

Germany

160

112

France

210

218

Total

370

330

Both countries now have more cheese and wine than they had before they specialised and traded. Germany has 10 million more bottles of wine and 12 million more kilograms of cheese. France has 10 million more bottles of wine and 18 million more kilograms of cheese. In a sense, their PPFs have moved out as a result of specialisation and trade.

这两个国家现在拥有的奶酪和葡萄酒都比他们专门化和贸易化之前的多。德国多了1000万瓶葡萄酒，多了1200万公斤奶酪。法国多了1000万瓶葡萄酒和1800万公斤奶酪。从某种意义上说，由于专业化和贸易，他们的PPF已经转移出去。

As with the absolute advantage example, it should be noted that we have assumed that there are no transport costs for the delivery of the exports of each product. Also, we have assumed that there are no negative externalities in the production process, or from the consumption of wine and cheese (which is definitely not the case in the real world!).

与绝对优势的例子一样，应该指出的是，我们假设每种产品的出口交货没有运输成本。此外，我们还假设在生产过程中，或者在葡萄酒和奶酪的消费中没有负外部性（现实世界中绝对不是这样的！）。

The lawyer and his secretary 律师和他的秘书

If the numerical example above doesn't make much sense, think of the concept of comparative advantage in terms of a lawyer and his secretary.

如果上面的数字例子没有太大的意义，可以从一个律师和他的秘书的角度来考虑比较优势的概念。

Assume that a lawyer can charge his services out at 100 pounds an hour (it is probably more nowadays!). Also assume that he/she happens to be a very quick typist, and can type 80 words a minute. His secretary is fairly good, typing 60 words a minute. The secretary is paid 12 pounds an hour.

假设律师可以以每小时100英镑的价格收取他的服务费（现在可能更多！）。还假设他/她恰好是一个非常快的打字员，每分钟可以打80个字。他的秘书也相当不错，每分钟能打60个字。秘书的工资是每小时12英镑。

The lawyer has an absolute advantage in being a lawyer and being a secretary! But he is much better at being a lawyer and only a little bit better at typing. He has a comparative advantage in the law and the secretary has a comparative advantage at typing.

这位律师在做律师和做秘书方面有绝对的优势！但他在做秘书方面要好得多。但是，他在做律师方面要好得多，而在打字方面却只有一点点优势。他在法律方面有比较优势，而秘书在打字方面也有比较优势。

If the lawyer decides to type a letter, or a report, because he is a bit quicker than the secretary, he would lose out overall. Let's say that it takes him 15 minutes to type a report. The secretary types 25% slower, so it would take him/her 20 minutes. It costs the lawyer four pounds to hire the secretary for 20 minutes, but if he types the report, he has wasted 15 minutes for which he could have earned 25 pounds being a lawyer!

如果律师决定打一封信，或一份报告，因为他比秘书快一点，他将在整体上输掉。比方说，他打一份报告需要15分钟。秘书的打字速度慢25%，所以他/她需要20分钟。律师雇秘书打20分钟要花4英镑，但如果他打报告，他就浪费了15分钟，而作为律师，他本可以赚到25英镑！这就是为什么他要花4英镑。