Comparative Advantage and Gains from Trade · 比较优势与贸易收益
| English | 中文 | Pinyin · 拼音 |
|---|---|---|
| comparative advantage/kəmˈpærətɪv ədˈvæntɪdʒ/ | 比较优势 | bǐ jiào yōu shì |
| absolute advantage/ˈæbsəluːt ədˈvæntɪdʒ/ | 绝对优势 | jué duì yōu shì |
| opportunity cost/ɒpəˈtjuːnɪti kɒst/ | 机会成本 | jī huì chéng běn |
| specialise/ˈspeʃəlaɪz/ | 专业化 | zhuān yè huà |
| terms of trade/tɜːmz ɒv treɪd/ | 贸易条件 | mào yì tiáo jiàn |
Why nations trade at all
- If a country could make everything more cheaply, why buy from abroad?
- Yet even then, trade leaves both countries better off.
- The reason is one of the most powerful ideas in economics.
- It rests on comparative advantage 比较优势, not on being best at everything.
国家为什么要贸易
- 如果一个国家什么都能造得更便宜,为什么还要从国外买?
- 可即便如此,贸易仍让两个国家都变得更好。
- 原因是经济学里最有力的观点之一。
- 它靠的是比较优势(comparative advantage),而不是样样都最强。
Absolute vs comparative advantage
- Absolute advantage 绝对优势 means making more of a good with the same resources.
- Comparative advantage means having the lower opportunity cost 机会成本 of making it.
- A country can hold the absolute advantage in everything, yet the comparative advantage in only some things.
- For trade, the rule that matters is comparative, not absolute.
绝对优势与比较优势
- 绝对优势(absolute advantage)是用同样的资源生产更多某种商品。
- 比较优势是生产它的机会成本(opportunity cost)更低。
- 一个国家可以在所有商品上都有绝对优势,却只在部分商品上有比较优势。
- 对贸易来说,起作用的是比较优势,而不是绝对优势。
Absolute or comparative? · 绝对优势还是比较优势?
Absolute advantage is about making more; comparative advantage is about the lower opportunity cost. Only comparative advantage decides who specialises. · 绝对优势看谁产量更多;比较优势看谁机会成本更低。只有比较优势决定谁专业化。
A country has a comparative advantage in a good when it has: · 一个国家在某商品上有比较优势,是当它:
Comparative advantage is about opportunity cost, not raw output. · 比较优势关乎机会成本,而非产量本身。
Work out who makes what
- Worked idea. In a day, Country A makes 12 wheat or 6 cloth; Country B makes 4 wheat or 4 cloth.
- A's opportunity cost of 1 cloth is $12/6 = 2$ wheat; B's is $4/4 = 1$ wheat — so B has the comparative advantage in cloth.
- A's cost of 1 wheat is $6/12 = 0.5$ cloth; B's is 1 cloth — so A has the comparative advantage in wheat.
算一算谁造什么
- 例题。 一天内,A 国造 12 小麦或 6 布;B 国造 4 小麦或 4 布。
- A 造 1 匹布的机会成本是 $12/6 = 2$ 小麦;B 的是 $4/4 = 1$ 小麦——所以 B 在布上有比较优势。
- A 造 1 单位小麦的成本是 $6/12 = 0.5$ 布;B 的是 1 布——所以 A 在小麦上有比较优势。
A: 12 wheat or 6 cloth. B: 4 wheat or 4 cloth. Who has the comparative advantage in cloth · 布料? · A:12 小麦或 6 布。B:4 小麦或 4 布。谁在布上有比较优势?
B gives up 1 wheat per cloth vs A's 2 — B has the lower opportunity cost in cloth. · B 每匹布放弃 1 单位小麦,A 放弃 2——B 在布上机会成本更低。
Country A makes 12 wheat OR 6 cloth in a day. What is the opportunity cost of ONE cloth, in wheat? · A 国一天造 12 小麦或 6 布。一匹布的机会成本(以小麦计)是多少?
Giving up 12 wheat frees enough to make 6 cloth, so each cloth costs $12/6 = 2$ wheat. · 放弃 12 单位小麦可换来 6 匹布,所以每匹布的成本是 $12/6 = 2$ 单位小麦。
Specialise, then trade
- Each country specialises 专业化 where its opportunity cost is lower (A in wheat, B in cloth).
- They then trade, and both consume beyond their own PPC.
- The terms of trade 贸易条件 must fall between the two opportunity costs for both to gain.
- This holds even though one country may be absolutely better at everything.
先专业化,再贸易
- 每个国家在机会成本更低处专业化(specialise)(A 造小麦,B 造布)。
- 然后进行贸易,双方都能消费到超出各自 PPC 的水平。
- 贸易条件(terms of trade)必须落在两者机会成本之间,双方才都获益。
- 即使一个国家样样都绝对更强,这也成立。
If one country is absolutely better at making everything, trade cannot benefit both. · 如果一个国家在生产一切上都绝对更强,贸易就无法让双方都受益。
As long as opportunity costs differ, both gain from specialising and trading. · 只要机会成本不同,双方都能从专业化和贸易中获益。
Each country should ______ in the good where its opportunity cost is lower. · 每个国家应在机会成本更低的商品上______。
Specialise by comparative advantage, then trade for the rest. · 按比较优势专业化,再贸易换取其余。
For both countries to gain, the terms of trade must lie: · 要让两个国家都获益,贸易条件必须落在:
A swap rate between the two costs leaves both better off than in isolation. · 介于两者成本之间的交换比率,让双方都比孤立时更好。
Comparative advantage is the lower opportunity cost — not making more (that is absolute advantage). Each country should specialise where its opportunity cost is lower and trade for the rest, gaining even if one is better at everything. The terms of trade sit between the two opportunity costs.
比较优势是更低的机会成本——不是产量更多(那是绝对优势)。每个国家应在机会成本更低处专业化,再贸易换取其余,即使一方样样都更强也能获益。贸易条件落在两者机会成本之间。