国际经济学课件第二章(第八版).克鲁格曼——西南财大

6.
Only two countries are modeled: domestic and foreign.
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A One Factor Ricardian Model (cont.)
• Because labor productivity is constant, define a unit labor requirement as the constant number of hours of labor required to produce one unit of output.
• The simple example with roses and computers explains the intuition behind the Ricardian model. • We formalize these ideas by constructing a slightly more complex one factor Ricardian model using the following simplifying assumptions:
country faces a trade off: how many computers or roses should it produce with the limited resources that it has?
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aLW is the unit labor requirement for wine in the domestic country. For example, if aLW = 2, then it takes 2 hours of labor to produce one liter of wine in the domestic country. aLC is the unit labor requirement for cheese in the domestic country. For example, if aLC = 1, then it takes 1 hour of labor to produce one kg of cheese in the domestic country.
Lecture 2: Labor productivity and comparative advantage: the Ricardian model
• Key reading

K&O(2011),International Economics: Theory and Policy . Chap.3 Rudiger Dornbusch, Stanley Fischer, and Paul Samuelson. "Comparative Advantage, Trade and Payments in a Ricardian Model with a Continuum of Goods." American Economic Review 67 (December 1977) pp.823-839.
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3-10
Production Possibilities Frontier
• What’s production possiblity frontier? • The production possibility frontier (PPF) of an economy shows the maximum amount of a goods that can be produced for a fixed amount of resources. • If QC represents the quantity of cheese produced and QW represents the quantity of wine produced, then the production possibility frontier of the domestic economy has the equation:
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Introduction
• The Ricardian model is based on technological differences across countries.
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Opportunity costs and comparative advantage
(cont.)
• Suppose that in the US 10 million roses can be produced with the same resources that could produce 100,000 computers.
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A One Factor Ricardian Model (cont.)
• Because the supply of labor is constant, denote the total number of labor hours worked in the domestic country as a constant number L.
aLCQC + aLWQW = L
Labor required for each unit of cheese production Total units of cheese production Labor required for each unit of wine production
Total amount of labor resources Total units of wine production
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3-7
A One Factor Ricardian Model (cont.)
1.
2.
Labor is the only resource important for production.
Is the opportunity cost for Peru to produce roses higher or lower comparing with US?
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3-6
A One Factor Ricardian Model
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Opportunity costs and comparative advantage
• The Ricardian model uses the concepts of opportunity cost to reflect comparative advantage.
4. 5.
The supply of labor in each country is constant.
Only two goods are important for production and consumption: wine and cheese. Perfect Competitive market.
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Production Possibilities Frontier(cont.)
• When the economy uses all of its resources, the opportunity cost is equal to the absolute value of the slope of the PPF, and it is constant when the PPF is a straight line.( Why PPF is usually a straight line in one factor model?)
Opportunity costs and comparative advantage
(cont.)
• For example, a limited number of workers could be employed to produce either roses or computers.
A
• Further reading

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3-1
Outline of Lecture2
• • • • • • • Opportunity costs and comparative advantage A one factor Ricardian model Production possibilities frontier (PPF) Gains from trade Wages and trade Misconceptions about comparative advantage comparative advantage with many goods.(not required) • Empirical evidence
• Suppose that in Peru 10 million roses can be produced with the same resources that could produce 30,000 computers. • Quick answer:


what's the opportunity cost of producing rose in Peru?
• What's the opportunity cost?
The
opportunity cost of producing something measures the cost of not being able to produce something else.
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Could
you suggest some variables to reflect the technological difference?
These
technological differences are reflected in differences in the productivity of labor.
Labor productivity varies across countries, usually due to differences in technology, but labor productivity in each country is constant across time.
3.
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3-11
Production Possibilities Frontier(cont.)
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• Quick answer:

A high unit labor requirement means low labor productivity or high labor productivity?.
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