1. Comparative Advantage and Gains from Trade

2. Overview Principle Five: Trade can make everyone better off
Voluntary exchange between people must be mutually beneficial…otherwise one side would cancel the deal.
Logic of specialization and exchange is clear for individuals: self-sufficiency would be hard.
Do you grow your own food or make your own clothes?

3. The Production Possibilities Frontier
The Production Possibilities Frontier: illustrates the different quantities of two goods an economy can produce given the available factors of production and current state of technology.
The Production Possibilities Frontier can be used to illustrate:
a) the concept of opportunity cost
b) the concept of economic efficiency
c) the concept of gains from trade

4. The Production Possibilities Frontier
Agricultural Goods
Points along the frontier are efficient.
Point B is inefficient
Point D is unattainable given current technology
Movement from Point A to Point C demonstrates opportunity cost. Opportunity cost of 300 more units high tech goods is 800 units of agricultural goods
3,000
2,800 A D
2,000 C
1,000 B
200
1,000
500
800
High Tech Goods

5. Shifts in The Production Possibilities Frontier
Agricultural Goods
A technological advance in high tech goods shifts the production possibilities outward. As a result, more of both goods can be produced.
3,000
2,200 B
2,000 A
800
900
1,000
1,500
High Tech Goods

6. Production Possibilities Frontier and Gains from Trade
The production possibilities frontier can also be used to analyze gains from trade.
Consider two men on a deserted island: Gilligan and Skipper.
Each has 6 hours a day to secure food.
Gilligan is better at collecting coconuts.
Skipper is better at fishing.

7. Productivity Table Coconuts Fish Gilligan Per hour: 2 1
In 6 hours:
Skipper
Per hour:
In 6 hours:

8. . . . Gilligan’s PPF Coconuts Fish
Gilligan likes to consume an equal number of fish and coconuts. 12
Without trade, his PPF allows him to consume four of each . 4 . 4 6
Fish

9. . . . Skipper’s PPF Coconuts 6 4 12 4 Fish
Skipper also likes to consume an equal number of fish and coconuts. . . 6
Without trade, his PPF allows him to consume four of each 4 . 4 12
Fish

10. Opportunity Costs Gilligan: Skipper: One more fish = 2 fewer coconuts
One more coconut = .5 fewer fish
Skipper:
One more fish = .5 fewer coconuts
One more coconut = 2 fewer fish

11. The Benefits of Exchange
If the men specialize in what they do best, trade will make them better off:
Coconuts Fish
Gilligan
Produce:
Trade:
Consume:
Skipper

12. Gilligan’s Exchange w/ Skipper
Coconuts
With trade, Gilligan specializes in collecting coconuts…. . 12
…and trades away six coconuts for six fish…
…after which he has more of both goods. . 6
Without trade, his PPF allows him to consume four of each 4 . 4 6
Fish

13. Skipper’s Exchange w/ Gilligan
Coconuts
Without trade, his PPF allows him to consume four of each
With trade, Skipper specializes in catching fish…. .
…and trades away six fish for six coconuts. . 6
…after which he has more of both goods. 4 . 4 6 12
Fish

14. The Principle of Comparative Advantage: An Overview
Differences in the costs of production determine the following:
Who should produce what
How much should be traded for each product
In the previous example, Gilligan could produce coconuts at a lower cost and the Skipper could produce fish at a lower cost.
Two ways to measure differences in costs of production:
The number of hours required to produce a unit of output (for example, one fish or one coconut).
The opportunity cost of sacrificing one good for another.

15. Comparative Advantage
Comparative Advantage: The comparison among producers of a good according to their opportunity cost.
In the previous example:
Gilligan’s opportunity cost of producing one more fish was two coconuts. Skipper’s opportunity cost of one more fish was .5 coconuts. Thus, Skipper has a comparative advantage in producing fish.
Skipper’s opportunity cost of producing one more coconut was 2 fish. Gilligan’s opportunity cost of one more coconut was .5 fish. Thus, Gilligan has a comparative advantage in producing coconuts.

16. Absolute Advantage
Absolute Advantage: The comparison among producers of a good according to their productivity.
In the previous example:
Gilligan required only 30 minutes to produce one coconut whereas the Skipper required one hour: Gilligan had an absolute advantage in collecting coconuts
Skipper required only 30 minutes to produce one fish whereas Gilligan required an hour: Skipper had an absolute advantage in fishing

17. Opportunity Cost and Comparative Advantage
When trading partners have absolute advantage in opposite goods, benefits of exchange are pretty clear…
Gilligan (coconuts) and Skipper (fish)
Colombia (coffee) and Chile (fish)
Saudi Arabia (oil) and New Zealand (sheep)
…but what if one trading partner has an absolute advantage in everything? Is trade still worthwhile?
Enter: Maryanne

18. Productivity Table Coconuts Fish Gilligan Per hour: 2 1
In 6 hours:
Maryanne
Per hour:
In 6 hours:

19. Absolute Advantage and Gains from Trade
Maryanne has an absolute advantage over Gilligan in the production of both goods
She is better off than he is in the absence of trade
Can Maryanne profit from trading with a bozo like Gilligan? Can Gilligan benefit from trade, too?
YES

20. . . . Maryanne’s PPF Coconuts 18 9 9 18 Fish
Maryanne also likes to consume an equal number of fish and coconuts. .
Without trade, her PPF allows her to also consume nine of each 9 . 9 18
Fish

21. The Benefits of Exchange
Coconuts Fish
Gilligan
Produce:
Trade:
Consume:
Maryanne
= = 5
= = 10

22. Gilligan’s Exchange w/ Maryanne
Coconuts
With trade, Gilligan specializes in collecting coconuts…. . 12
…and trades away seven coconuts for five fish…
…after which he has more of both goods. . 5
Without trade, his PPF allows him to consume four of each 4 . 4 5 6
Fish

23. Maryanne’s Exchange w/ Gilligan
Coconuts .
With trade, Maryanne moves toward a specialization in fishing…. 18
…and trades away five fish for seven coconuts… . 10
…after which she has more of both goods. 9 . . 3 9 10 15 18
Fish

24. Comparative Advantage and Gains from Trade
The benefits of trade ultimately come from comparative (not absolute) advantage
Everyone has a comparative advantage in something, so opportunities for exchange are everywhere
Even when a person or a country has an absolute advantage in everything, they can still benefit from trade due to comparative advantage.

25. International Trade
Trade at international prices allows a nation to consume beyond its PPF
Manufacturing goods
Production and consumption in the absence of trade .
Consumption with trade .
Production with trade .
International trade line
Agricultural goods