Basics of Two-Country Trade: The Standard Trade Model

Trade Between Two CountriesJapan Europe World Trade

P D S D S D S J E

10 0 11 0 9 0 20 11 9

9 0 10 2 8 2 18 10 6

8 0 9 4 7 4 16 9 3

7 0 8 6 6 6 14 8 0

6 0 7 8 5 8 12 7 -3

5 0 6 10 4 10 10 6 -6

4 1 5 12 3 13 8 4 -9

3 2 4 14 2 16 6 2 -12

2 3 3 16 1 19 4 0 -15

1 4 2 18 0 22 2 -2 -18

0 5 1 20 0 25 1 -4 -20

Trade Between Two Countries

• Assume a two-country world

• When these two countries begin trading…– The price of the traded good

• decreases in the country with the higher autarky price, and

• increases in the country with the lower autarky price

– Eventually, the price becomes the same in both countries

– This global price lies somewhere between the two autarky prices

Trade Between Two Countries

• When two countries begin trading…– the country with the higher autarky price

imports the good, and– the country with the lower autarky price

exports the good– global quantity demanded = global quantity

supplied– exports = imports (in quantity and market

value)

Graphical analysis of two-country trade

• Now, let us review our numerical analysis using graphs!– Economists love graphs!

This is how the worldwide free trade price is determined. Note that the free trade price ( ) must lie between the two countries’ autarky prices ( ).

Price

Europe Japan World+ = Quantity

Europe has the higher autarky price. Europe becomes the importing country. Prices fall. Production falls.

Japan has the lower autarky price. Japan becomes the exporting country. Prices rise. Production rises.

Note that Japan’s exports ( ) equal Europe’s imports ( ).

Japan: The Exporting Country

Priceof Steel

0Quantityof Steel

Domesticsupply

Priceaftertrade World

price

DomesticdemandExports

Pricebeforetrade

Domesticquantity

demanded

Domesticquantitysupplied

Europe: The Importing Country

Priceof Steel

0 Quantity

Priceafter

trade

Worldprice

of Steel

Domesticsupply

Domesticdemand

Imports

Domesticquantitysupplied

Domesticquantity

demanded

Pricebeforetrade

Price

Europe Japan World+ = Quantity

If the autarky equilibrium price is the same for both countries, no trade will occur even when trade is allowed. That is, similarity = no trade.

Prices: nominal and relative

• So far, I have been not been fully clear about how prices are measured

• When the price of a good is measured in currency units, it is called a nominal price– Example: the nominal price of ice cream is

$4.00 per quart– Example: the nominal price of coffee is $1.00

per cup

Prices: nominal and relative

• When the price of one good is measured in units of another good, it is called a relative price– Example: suppose the nominal price of ice cream

is $4.00 per quart and the nominal price of coffee is $1.00 per cup.

– Then the relative price of ice cream is 4 cups of coffee per quart.

– And the relative price of coffee is ¼ quarts of ice cream per cup

• In my lectures on international trade, when I say “price” I mean “relative price”

Similarity = No Trade

• If the pre-trade (or autarky) relative prices (of one good in terms of another) are the same for the two countries, no trade will occur. – On relative prices, see “Relative Prices and Supply” on page 31

of KO.

Price

Europe Japan World+ = Quantity

As we saw before, if the autarky equilibrium price is not the same for both countries, trade will occur when trade is allowed. That is, dissimilarity = trade.

Dissimilarity = Trade

• Trade will occur if the pre-trade (or autarky) relative price of one good in terms of the other is not the same for the two countries.

• The free trade relative price will be neither higher than the two autarky prices, nor lower.

• Therefore, when the autarky relative prices are unequal, the free trade relative price must be different from the autarky relative price for at least one of the two countries.

Reasons For Dissimilarity

• Three theories that explain why autarky prices may be high in some countries and low in others:– Ricardian Theory– Specific Factors Theory– Heckscher-Ohlin Theory

Effect of Trade on Prices

• When autarky ends and free trade begins, the relative price of any given good will– increase in the country where it used to be

cheaper in autarky, and– decrease in the country where it used to be more

expensive in autarky

• This follows from the fact that the free trade relative price of any traded good, in general, lies somewhere between the two autarky relative prices

Effect of Trade on Production

• If the price of good X (relative to good Y) increases, then, in a country that is otherwise unchanged, – the production of X will increase and – the production of Y will decrease

• See “Production Possibilities and Relative Supply” on page 89 and

Figure 5-2 of KO.

Effect of Trade on Consumption

• If, under free trade, the price of good X (relative to good Y) increases, then, in a country that is otherwise unchanged, – the consumption of good X will decrease if it is the

imported good and – may either decrease or increase if it is the exported

good.

• Similarly, – the consumption of Y will increase if Y is the imported

good and – may either increase or decrease if it is the exported

good.• See Figure 5-4 of KO.

Effect of Trade on Consumption

• The effect of an increase in the price of beef (relative to steel) on the consumption of beef works through two channels:– Substitution effect: buy less of whatever has

become more expensive and more of whatever has become less expensive

– Income effect: if a change in a price makes you richer, buy more of all things, across the board; if a change in price makes you poorer, buy less of all things, across the board

Effect of Trade on Consumption

• Consider an increase in the price of beef (relative to steel)– Substitution effect: buy less beef and more

steel– Income effect:

• if you export beef, hooray, you are now richer! So buy more of both beef and steel

• If you import beef, you are poorer. So, buy less of both beef and steel

Effect of Trade on Consumption

Beef price ↑ Exports beef, imports steel Imports beef, exports steel

beef steel beef steel

Substitution effect ↓ ↑ ↓ ↑

Income effect ↑ ↑ ↓ ↓

Total effect ambiguous ↑ ↓ ambiguous

Trade Reflects Comparative Advantage

• When autarky ends and free trade begins, each country – increases its production of the good in which it

has a comparative advantage and – exports that good.

• In other words, free trade follows the principle of comparative advantage.

Comparative Advantage

• A country is said to have a comparative advantage in the production of a good if, in autarky, the opportunity cost of the good is smaller in that country.– The opportunity cost of good X is the amount of

good Y that will have to be sacrificed when an additional unit of X is produced

– In a perfectly competitive economy, the opportunity cost of good X equals the relative price of good X.

– See “The Concept of Comparative Advantage” on page 28 of KO for more on “opportunity cost” and “comparative advantage”.