1. An Introduction to International Economics Second Edition
CHAPTER T W O
An Introduction to International Economics Second Edition
Comparative Advantage
Dominick Salvatore
John Wiley & Sons, Inc.

2. The basic questions of international trade
What is the basis of trade?
Absolute Advantage
Comparative Advantage

3. The basic questions of international trade
What is the basis of trade?
What are the gains from trade?
The models of Absolute and Comparative Advantage show that the gains from trade are increased consumption gained through specialization in production and trade.

4. The basic questions of international trade
What is the basis of trade?
What are the gains from trade?
What is the pattern of trade?
What determines the pattern of specialization that drives international trade?

5. The Mercantilists What is wealth?
The Mercantilist answer was the stock of precious metals possessed by a country.

6. The Mercantilists What is wealth? How can precious metals be obtained?
Extraction from naturally occurring stocks
This option is available to few countries

7. The Mercantilists What is wealth? How can precious metals be obtained?
Extraction from naturally occurring stocks
Earn precious metals through exports of goods and services
Since payment for exports is made with precious metals, exporting causes precious metals to flow into a country
Similarly, since payment for imports is also made with precious metals, importing causes precious metals to flow out of country

8. The Mercantilists What is wealth? How can precious metals be obtained?
The natural conclusion – exports must exceed imports for a country to become wealthy!

9. The Mercantilists What is wealth? How can precious metals be obtained?
The natural conclusion – exports must exceed imports for a country to become wealthy!
Can this condition hold for all countries?
No!
Therefore, the wealth of one country must come at the expense of another country.

10. The Mercantilists What is wealth? How can precious metals be obtained?
The natural conclusion – exports must exceed imports for a country to become wealthy!
Can this condition hold for all countries?
Mercantilist policy
Strict government control over economic activity to ensure a positive trade balance

11. Are precious metals “wealth”?
To the Mercantilists, yes.
Modern measures of wealth are based on a country’s ability to produce the goods and services that improve quality of life.
Hence, the Mercantilist conclusion is based on a definition of wealth that differs significantly from modern notions of wealth.
This distinction leads to very different conclusions about how to become a wealthy nation.

12. Absolute advantage Built on the ideas of Adam Smith
The Library of Economic Liberty Biography of Adam Smith
Absolute advantage exists between nations when they differ in their ability to produce goods.
More specifically, absolute advantage exists when one country is good at producing one item, while another country is good at producing another item.

13. An example of absolute advantage
Countries
Scotland
Mexico
Goods
Coffee beans
Wool

14. An example of absolute advantage
How does specialization and trade advantage Scotland?
By reducing coffee bean production, resources are freed for producing more wool
Each hour of production change costs 1 unit of coffee beans but gains 4 units of wool

15. An example of absolute advantage
How does specialization and trade advantage Scotland?
Scotland can send 3 units of wool to Mexico and receive 7 units of coffee beans back
Thus, by specializing in production Scotland gains 1 unit of wool and 6 units of coffee per hour of production moved

16. An example of absolute advantage
Does specialization and trade also advantage Mexico?
By reducing wool production, resources are freed for producing more coffee beans
Each hour of production change costs 2 units of wool but gains 10 units of coffee beans

17. An example of absolute advantage
Does specialization and trade also advantage Mexico?
Mexico can send 7 units of coffee beans to Scotland and receive 3 units of wool back
Thus, by specializing in production Mexico gains 1 unit of wool and 3 units of coffee beans per hour of production moved

18. Policy recommendations from absolute advantage
Specialization and trade advantage both countries
Therefore, the best policy is to allow producers and consumers in both countries unfettered access to goods from both countries to maximize the number of advantageous trades that can occur.
In other words, laissez-faire.
The policy of minimum government interference with economic activity.

19. A fatal flaw?
Absolute advantage requires one country to be better at production of one product and another country to be better at production of another good for specialization and trade to be mutually advantageous.
What if one country is better at everything?
The theory of comparative advantage provides this answer.

20. Comparative advantage
Built on the ideas of David Ricardo
The New School History of Economic Thought Biography of David Ricardo
WWW Link
The law of comparative advantage says a nation should specialize in and export the commodity in which its absolute disadvantage is smaller (this is the commodity of its comparative advantage), and should import the other commodity.
Implications of comparative advantage are best seen through example.

21. An example of comparative advantage
Countries
Scotland
Mexico
Goods
Coffee beans
Wool
The difference lies in the relative productivity of the countries
In this case, Mexico is more productive at generating both goods.

22. An example of comparative advantage
How does specialization and trade advantage Mexico?
By reducing wool production, resources are freed for producing more coffee beans
Each hour of production change costs 5 units of wool but gains 10 units of coffee beans

23. An example of comparative advantage
How does specialization and trade advantage Mexico?
Mexico can send 9 units of coffee beans to Scotland and receive 7 units of wool back
Thus, by specializing in production Mexico gains 1 unit of coffee beans and 2 units of wool per hour of production moved

24. An example of comparative advantage
Does specialization and trade also advantage Scotland?
It does. To see this consider consider Scotland trading two hours of output.
Two hours of production change from coffee beans to wool costs 2 units of coffee beans but gains 8 units of wool

25. An example of comparative advantage
Does specialization and trade also advantage Scotland?
Scotland can send 7 units of wool to Mexico, receiving 9 units of coffee beans in return
Thus, by specializing in production Scotland gains 1 unit of wool and 7 units of coffee beans

26. Implications of comparative advantage
Laissez-faire still holds
Gains need not be equal
Hours of work traded need not be equal but the advantage still exists
Trade is based on the existence of relative – not absolute – production advantages

27. Does money alter the story?No
Suppose the costs of production are as given below
Mexico: 100 pesos/hour
Scotland: 4 pounds/hour
Suppose the exchange rate between pesos and pounds is 1£ = 10P
This gives the unit costs indicated in the chart
4£ ÷ 1 unit = 4£ per unit
4£ x 10P/£ = 40P per unit

28. Does money alter the story?No
Suppose the costs of production are as given below
Mexico: 100 pesos/hour
Scotland: 4 pounds/hour
Suppose the exchange rate between pesos and pounds is 1£ = 10P
This gives the unit costs indicated in the chart
4£ ÷ 4 units = 1£ per unit
1£ x 10P/£ = 10P per unit

29. Does money alter the story?No
Suppose the costs of production are as given below
Mexico: 100 pesos/hour
Scotland: 4 pounds/hour
Suppose the exchange rate between pesos and pounds is 1£ = 10P
This gives the unit costs indicated in the chart
100P ÷ 10 units = 10P per unit

30. Does money alter the story?No
Suppose the costs of production are as given below
Mexico: 100 pesos/hour
Scotland: 4 pounds/hour
Suppose the exchange rate between pesos and pounds is 1£ = 10P
This gives the unit costs indicated in the chart
100P ÷ 5 units = 20P per unit

31. Does money alter the story?
At these prices goods will naturally flow from the cheaper market (Scotland for wool, Mexico for coffee beans) to the more expensive market.
Again, this demonstrates the law of comparative advantage but through prices not relative outputs.

32. Does the source of the productive difference matter?No
The original idea of comparative advantage was based on the labor theory of value.
The labor theory of value holds that costs and prices are solely determined by the labor content of an item.
The examples given above rely on opportunity cost.
Opportunity cost holds that the cost of an item is the amount of another item the must be given up to release sufficient resources to produce one more unit of the first item.

33. The production possibility frontier
The production possibility frontier (PPF) identifies the maximum combinations of two products that a nation can produce by fully utilizing all factors of production with the best technology available.
Consider the production possibilities schedule for an example:
United States
Wheat
Cloth
180
150 20
120 40 90 60 80 30
100

34. The production possibility frontier
The production possibility frontier (PPF) identifies the maximum combinations of two products that a nation can produce by fully utilizing all factors of production with the best technology available.
Consider the production possibilities schedule for an example:
United Kingdom
Wheat
Cloth 60 50 20 40 30 80 10
100
120

35. Constructing the PPF United States Wheat Cloth 180 150 20 120 40 90 60
150 20
120 40 90 60 80 30
100

36. Constructing the PPF United States Wheat Cloth 180 150 20 120 40 90 60
150 20
120 40 90 60 80 30
100

37. Constructing the PPF United States Wheat Cloth 180 150 20 120 40 90 60
150 20
120 40 90 60 80 30
100

38. Regions of the PPF Productive maximum Underutilized resources
Unattainable with existing resources and technology

39. Trade with the PPF model
Suppose the US and the UK have the PPFs given to the right

40. Trade with the PPF model
Suppose the US and the UK have the PPFs given to the right
Further suppose that each country produces and consumes at the marked spot in the absence of international trade
(90W, 60C)
(40W, 40C)

41. Trade with the PPF model
Can specialization and trade lead to more aggregate production and consumption?
If the US specialized in wheat production and the UK in cloth production, aggregate production would increase from 130W to 180W and from 100C to 120C.
(90W, 60C)
(40W, 40C)

42. Trade with the PPF model
This increased production would allow each country to consume at a point outside of its PPF as indicated by the blue lines in the graphs.
The increased consumption is the gains from trade.
(110W, 70C)
Production
Production
(70W, 50C)

43. Trade with the PPF model
(110W, 70C)
Production
(70W, 50C)