• what nations export and import what goods
• with what other nations
• under which economic, geographic, and political circumstances,
• with what consequences.

MERCANTILISM
1500-1800

•  not a full-blown trade theory (see above);  rather,
•  an economic policy of governmental accumulation of wealth, in the form of gold bouillon for:
•  domestic control
•  investment
•  international expansion
•  reflects the era of nation-building and the shifting of European political power from feudal lords and the church to national sovereigns;  also reflects and supports the principal source of wealth -- trading

ABSOLUTE ADVANTAGE
1776:  Adam Smith's The Wealth of Nations

Political and economic liberalism found their expression in Smith's argument that the wealth of nations depends upon the goods and services available to their citizens, rather than the gold reserves held by the sovereign.

Maximizing this availability depends, first, on putting all resources to use, and then, on the ability --

•  to obtain goods and services from where they are produced most cheaply (because of “natural” or “acquired” advantages), and
•  to pay for them by production of the goods and services produced most cheaply in the country,
•  with costs measured in terms of direct and "embedded" labor inputs.

 - development of specialized equipment;
 - labor training and specialization;
 - long "runs" of one product.

The consequent trade policy is relatively free trade, so that a country should import goods that would be produced more expensively internally, where expense is measured according to the labor theory of value.
These imports are to be paid for by the production of goods that the country can produce with less use of labor per unit.
Exports flow from the country that can produce a product most cheaply.
 

COMPARATIVE ADVANTAGE
• 1817:  David Ricardo's On the Principles of Political Economy and Taxation
• The possibility of system-wide gains from trade persists, even when a given country has an absolute advantage in the production of no product.
• Specialization and trade should occur according to the relative opportunity costs of production in each country, measured in terms of the alternative production given up to produce a tradable good.

 Example:

• The opportunity cost of tea in Sri Lanka is 1 unit wheat;  the opportunity cost of tea in the US is 1.25 units wheat.  Sri Lanka has comparative advantage in tea production, despite its absolute disadvantage in the production of each commodity.
• To test for comparative advantage in the production of commodity A in a 2X2 model:  for which country is the opportunity cost of A smaller -- which is to say, for which country is the ratio of  resources required for a unit of A to the resources required for a unit of B smaller?
• 10/10 < 5/4, thus, the comparative advantage of Sri Lanka is commodity 1, tea.
• Although the US has an absolute advantage in the production of both tea and wheat, the US has a comparative advantage only in the production of wheat.  This is because its advantage in wheat is comparatively greater than its advantage in tea [Daniels and Radebaugh, 8th ed., p. 202].

• trade is gainful when a_i/b_i (the ratio of the costs of producing a and b in country i) is not equal to a_j/b_j (the ratio of the costs of producing a and b in country j)
• if  a_i/b_i < a_j/b_j, then i will export a and import b, so long as exchange rates allow:
• a_i/a_j < C_i/C_j < b_i/b_j  (which is to say that the exchange rate is not so extreme as to wipe out the differences in opportunity costs for each item across the two countries).

  US beef costs  $10 in the US
  US cameras cost $20 in the US
  Japanese beef costs ¥5000 in Japan
  Japanese cameras cost ¥1000 in Japan

Q:  What would make the dollar fall so much against the yen that a dollar would buy fewer than 50 yen, and this bilateral trade would end?  (That is, in a world where neither currency was used for other international purposes, and where there was no monetary policy).
A:   Such a low Japanese demand for US beef and such a high American demand for Japanese cameras that the exchange rate fell this low.

This relative demand for products from trading partners, expressed via its effect on exchange rates, determines the division of gains from trade.

• At $1 = ¥200, the US will import 2 cameras for each unit of beef it exports;  this is 1.5 more cameras than it could make domestically in lieu of one unit of beef;  the US gain from trade is 1.5 cameras per unit of beef.
• At $1 = ¥183.33, the US will import 1.83 cameras for each unit of beef it exports;  the gain from trade becomes 1.33 cameras per unit of beef.
• At $1 = ¥120, the US will get $10 = ¥1200 for each unit of beef it exports to Japan;  this would allow the US to import 1.2 cameras (at ¥1000 each);  this is 0.7 more camera than the US could make domestically at the opportunity cost of 1 unit beef, so the US gains from trade is 0.7 camera/beef.

 Simplified,  country 1's gains from trade = G₁ = (A₁/B₂)(C₂/C₁) - a₁/b₁

• The first ratio (A₁/B₂) is the ratio of (i) the unit price that Country 1's exports fetch on the world market (in terms of Country 1's currency) to (ii) the unit price that Country 2's exports fetch on the world market (in its currency).
• The second ratio (C₂/C₁)is the exchange rate:  the "price" of the exporting country's currency, which (without capital or money markets) is also a measure of the relative demand for that country's exports.
• The third ratio (a₁/b₁) is the opportunity cost of producing the exported product in the exporting country.
• (A₁/B₂)(C₂/C₁) is what Country 1 can get in return for exporting a unit of a
• a₁/b₁ is what Country 1 gives up as it produces a unit of a
• So can you see why (A₁/B₂)(C₂/C₁) - a₁/b₁ is the "gains from trade"?  Wait, ask yourself -- can you see why?
  

• increases with the relative unit price of Country 1's vs. Country 2's export items (this reflects the global supply/demand balance for these items),
• increases with strength of the Country 1's currency, and
• decreases with the opportunity costs (in Country 1) of producing the exported item.

As you think about this, and view the graphs in the textbook (Figs. 6.2 and 6.3), you'll recognize that we're making some assumptions:

1. We assume that national production is on the production possibility frontier (PPF), with no un-used factors (e.g., no unemployment).  If some available and relevant factors are not being used (e.g., labor unemployment in the export sector), then we can't clearly say that producing more of the export item would mean producing less of other items. 
   
2. We assume that factors are homogeneous within a country (e.g., L is perfectly substitutable across individuals and across sectors), so that workers, capital, and resources not used in one sector can work in another.
3. To make the numerical example simpler, I've assumed that prices equal costs (including a standard rate of return to capital and entrepreneurship).  That's not always the case:  sometimes prices are much higher than costs (e.g., in a monopoly), and sometimes international prices are lower than domestic costs (that's called "dumping").  We can deal with this by recognizing that a₁ might differ from A₁ and b₂ might differ from B₂.
4. We've ignored transportation costs -- but we could implicitly include them in A₁ and B₂ in the first term of our gains-from-trade equation -- or we could add them in as a variable in the first term -- this would allow us to show what happens with transportation costs fall (e.g., with containerization) or rise (e.g., with higher fuel prices).
5. We assume that factor prices reflect the value of marginal product attributable to the factors.  In reality, this is affected by the competitive structure of the industry (higher but declining in a monopolistic or oligopolistic industry), the nature of the factor markets (supply is restricted in the case of unionized L or the guild professions), and finally, wages/salaries are not solely determined by economic forces.

These are all problems with using traditional trade theory to understand and to prescribe trade flows in the current economy.
 

FACTOR  PROPORTIONS
1935:  Bertil Ohlin's Interregional and International Trade, based on earlier work by Eli Heckscher

What explains the differences in opportunity costs for producing the same product in different countries?  Possibilities include skill or technology (including a preference for producing in different ways), availability of materials or resources, or the pricing of inputs.

Assuming:
1) ubiquitous technology (the same everewhere),
2) general preferences to use the best available methods,
3) perfect competition in domestic factor markets (which should push factor prices to reflect their opportunity costs),
4) input requirements that differ across different products, but
5) only one particular mix of inputs for each different product, and
5) immobility of factors,
comparative advantage should depend on relative factor availability.

• "A country has a comparative advantage in the production of goods that use relatively large amounts of its abundant factors of production and a comparative disadvantage in the production of goods that use relatively large amounts of its scarce factors of production." Goods trade can be considered the indirect trade of factor services [Root, p.69].
 --> What is meant by abundant and scarce?  Measured by relative prices received by an additional unit of two factors, in one country versus that relationship in another country -- in other words, geography.

Complications:
1) heterogeneous factors -- of differing quality for specific production processes
2) substitution within a production function (a given product can be made with different proportions of inputs, depending on the relative prices of inputs in different places or at different times)
3) raw-material extraction is based on absolute advantage
 
 

LEONTIEF  PARADOX
1953:  Wasily Leontief published "Domestic production and foreign trade: the American capital position re-examined" in Proceedings of the American Philosophical Society (v.97).
1956:  Wasily Leontief published "Factor proportions and the structure of American trade: further theoretical and empirical analyses" in Review of Economics and Statistics  (v.38):

 Using data available from the 1947 input-output (I-O) model of the US economy, Leontief calculated the K and L requirements for the production of $1 million of US exports and $1 million of US production in import-competing industries.  He found that the former required a higher proportion of L than the latter.  [paraphrased from Hirsch, 1967: pp.8-9].
 · explain I-O and how such a model could be used to identify export sectors (rows with large entries in the X column);  L and K inputs;  US imports from trade data

• The paradox:  the US is considered K-rich, and US L was very expensive compared to L in other countries.  Analogous results were found in Japan, which was then L-rich and K-poor, yet Japanese exports were more K-intensive than Japanese production in sectors that faced import competition.

Possible explanations of the Leontief paradox (see a similar exposition by E.K. Choi)

1. US demand for K-intensive products outstripped its capacity to provide them domestically.  [No.]

2.  "Factor-intensity reversal" — Leontief had no idea of the input mix for manufacturing in other countries;  he measured the K-intensity of US production in import-competing industries, not of US imports.  If L is expensive in the US, then US industries facing import competition would have to reduce their use of L, by substituting K.  However, this would mean that production functions (i.e., input mix;  technology) vary for the same products in different places, which renders the Heckscher-Ohlin theorem nearly useless.  [Insufficient data, but this is a powerful argument for limiting empirical conclusions to the specifics of the data used].

3.  Perhaps international trade flows were not rationalized according to comparative advantage in 1947, immediately after the destruction and disruption of WW2.  After all, comparative advantage is a normative concept.  [Empirically, a partial explanation, when nations' import restrictions were considered].

4.  The US imported natural-resource commodities whose extraction is K-intensive, but in which other nations have an absolute advantage.  [Empirically, a partial explanation;  the paradox was more apparent in US bilateral trade with resources-rich countries (e.g., Canada), and was less strong when natural-resource sectors were excluded.]

5.  "Human-skills theory" — L is a heterogeneous factor, and should be analyzed as separate factors according to skills levels.  Perhaps the US is actually skilled- and technical-L rich, and therefore has a comparative advantage in production that requires much skilled or technical L.  H-O formulations should be expanded to allow for more than one L factor.  [Difficult to test, but can be added to the H-O theorem].  Related to this is the recognition of international differences in factor productivity.  US labor is more productive than the labor of most countries (because of skills, work organization, capital/worker, and technology), and is paid more per hour;  this helps explain why US labor looms larger as a cost in US exports.

6.  Technology itself is a nation-specific factor of production, rather than being a universal attribute of production.  Furthermore, technology is a factor that is produced within a given nation (much like a commodity), but is not perfectly mobile or tradable.  This kind of thinking has led to "neo-technology theories of trade" (see below).

7.  The US Government and private companies lent (or otherwise invested) so much capital in particular sectors of particular foreign economies, that these enclaves became, essentially, capital-rich.  [Thanks, Mike, for this suggestion.  Empirically, it probably doesn't play an important role in Leontief's 1947 data, but it (a) does conceptual damage to the factor-proportions theory because it implies that capital, a factor, is mobile, and (b) it presages the model of the international product life cycle, below].

PRODUCT  LIFE  CYCLE
• Raymond Vernon, 1966, "International trade and investment in the product life cycle"

• Concepts of product cycles had been developed in industrial economics and in marketing since the 1920's.  Vernon, however, became concerned with the technological bases for PLCs in the late 1950s. with his work on the New York Regional Plan.  He later extended these concerns to the international realm.
• Concerned with only certain products:

 · manufactured goods (or services that can be produced remotely from consumption, like call centers)
 · income-elastic demand
 · L-saving in use

 With these assumptions, Vernon built a story of these particular kinds of products facing
1) introduction in the highest-income, highest-wage country where the products found their first demand;  production is small-scale, changing, expensive, and uses highly skilled L;  demand is not very price-elastic, because of differentiation, and the nature of pioneering adopters
2) growth of demand and production in the original country, with declining costs and prices;  some export demand from countries with lower incomes and wages — the high-wage, L-scarce country is exporting L-intensive products
3) maturity of demand in the original country, with standardized and increasingly K-intensive production;  establishment of foreign operations in newer markets to serve them and to overcome real or threatened trade barriers
4) decline of product demand in the original country, with increasing competition from other suppliers and other products;  the cost pressure and the ability to embody the technology in K equipment and SOP pushes production "offshore" to low-wage countries, using financial K and K equipment from the originating country — the high-wage, L-scarce country is importing K-intensive products, because the K and technology are mobile within the MNC, while the less-expensive L is not mobile.

This helps resolve the Leontief paradox by explaining, for a limited class of goods, US exports of these goods while they are L-intensive and import of these same goods when they are K-intensive.

However, this model differs from the Heckscher-Ohlin theorem:

•  technology changes over time, from L toward K;
•  the mobility of technology changes over time
•  standardized technology and financial K are mobile factors within the MNC

TECHNOLOGY AND TRADE
The “new growth theory” and “new trade theory”:  Romer, Krugman, Helpman:  1980s.
See The Royal Swedish Academy of Sciences descriptions of Paul Krugman's contributions to trade theory and economic geography:  general;  technical.
See a short video on Paul Krugman and "new trade theory:  (here)

Six assumptions: 

1) Technology is an explicit factor of production, but one that is itself produced with inputs of capital and labor (and thus endogenous to the model of growth). 

2) However, the production of new technology reflects decreasing returns to the application of capital and labor (doubling the resources allocated to new technology does not immediately double the rate of technological advance). 

3) The production of new technology creates externalities:  all the benefits of new technology can't be appropriated by the entity (firm) that invests the resources to create the technology. 

4) There are increasing returns to scale in the use of technology (a little technology goes a long way -- can be used to improve quality or reduce cost of infinite number of units).  More generally, there are increasing returns (economies of scale) for the facility, organization (company), and country that specializes in a specific product.

5) While technology is mobile (across companies and countries), there is imperfect mobility of the ability to use technology, based on localized investments in infrastructure, institutions, and labor.

6) Most importantly, says Krugman, is the assumption of increasing returns to scale (unit costs of production fall with increased scale of output).  For advanced manufactures and for many services, this results in benefits from specialization (the more a company or country produces of a very specific item, the lower the opportunity costs of production).  These benefits include the ability to use and reuse specialized technology, equipment, and even reputation, at little additional cost.  This helps explain a country importing and exporting in the same industry -- the imports and exports can actually be different specific forms of the same type of product (automobiles, aircraft, financial services...).

Results: 

 1) To the extent that individual companies cannot appropriate all the returns to their investment in new technology (because of externalities in the development and deployment of technology),

Policy implications:
Thus, there may be a role in government support of technology, via measures such as

•  R&D tax credits
•  trade policy to support key, technology-improving sectors
• "technology infrastructure"

TRADE  TRAPS
Specialization and trade according to comparative advantage may maximize world production, but under some circumstances it may not lead to increased wealth and living standards in poorer countries.  Two of these "trade traps":

IMMISERATING  TRADE  (concept developed by Jagdish Baghwati):  If a country's imports depend on its export of basic, raw commodities, the country may face an inability to increase export earnings for three reasons, each related to the first term in our "gains from trade" model, above:

1. Raising prices will reduce demand by a greater proportion (because most raw commodities can be accessed from other countries, and because most raw commodities have substitutes)
2. Lowering prices will not increase demand by an equal proportion (because world demand for many commodities does not increase substantially because of a price decline:  think about world demand for copper)
3. As the world economy increases, the world demand for many raw commodities increases at a slower rate (demand is income inelastic).