Examine individual changes

'The '''law''' or '''principle of comparative advantage''' holds that under [[free trade]], an agent will produce more of and consume less of a good for which they have a comparative advantage.<ref>{{cite book|last1=Dixit|first1=Avinash|last2=Norman|first2=Victor|title=Theory of International Trade: A Dual, General Equilibrium Approach|year=1980|publisher=Cambridge University Press|location=Cambridge|page=2}}</ref> '''Comparative advantage''' is the economic reality describing the work [[gains from trade]] for individuals, firms, or nations, which arise from differences in their [[factor endowments]] or [[technological progress]].<ref>{{cite book|last1=Maneschi|first1=Andrea|title=Comparative Advantage in International Trade: A Historical Perspective|year=1998|publisher=Elgar|location=Cheltenham|page=1}}</ref> In an [[economic model]], [[agent (economics)|agents]] have a comparative advantage over others in producing a particular [[Goods (economics)|good]] if they can produce that good at a lower relative [[opportunity cost]] or [[autarky]] price, i.e. at a lower relative [[marginal cost]] prior to trade.<ref name="uslabor">{{cite web|url=http://www.bls.gov/bls/glossary.htm|title=BLS Information |date=February 28, 2008|work=Glossary|publisher=U.S. Bureau of Labor Statistics Division of Information Services |accessdate=2009-05-05}}</ref> One does not compare the monetary costs of production or even the resource costs (labor needed per unit of output) of production. Instead, one must compare the opportunity costs of producing goods across countries.<ref>{{cite web|title=The Theory of Comparative Advantage: Overview|url=http://catalog.flatworldknowledge.com/bookhub/reader/28?e=fwk-61960-chab#fwk-61960-ch02_s02|website=Flat World Knowledge|accessdate=23 February 2015}}</ref> [[David Ricardo]] developed the classical theory of comparative advantage in 1817 to explain why countries engage in [[international trade]] even when one country's workers are more efficient at producing ''every'' single good than workers in other countries. He demonstrated that if two countries capable of producing two commodities engage in the [[free market]], then each country will increase its overall consumption by exporting the good for which it has a comparative advantage while importing the other good, provided that there exist differences in [[labor productivity]] between both countries.<ref>Baumol, William J. and Alan S. Binder, 'Economics: Principles and Policy', [https://books.google.com/books?id=6Kedl8ZTTe0C&lpg=PA49&dq=%22law%20of%20comparative%20advantage%22&pg=PA50#v=onepage&q=%22law%20of%20comparative%20advantage%22&f p. 50]</ref><ref name="econbook">{{cite book |last1=O'Sullivan |first1=Arthur |authorlink1=Arthur O'Sullivan (economist) |last2=Sheffrin |first2=Steven M. |title=Economics: Principles in Action |url=https://www.amazon.com/Economics-Principles-Action-OSullivan/dp/0130630853 |accessdate=May 3, 2009 |edition=2nd |series=The Wall Street Journal: Classroom Edition |year=2003 |origyear= January 2002|publisher= Pearson Prentice Hall: Addison Wesley Longman|location=Upper Saddle River, New Jersey |isbn=0-13-063085-3 |page= 444 }}</ref> Widely regarded as one of the most powerful<ref>{{cite web|url=http://internationalecon.com/Trade/Tch40/T40-0.php |title=International Trade Theory and Policy|author=Steven M Suranovic|year=2010}}</ref> yet counter-intuitive<ref>{{cite web|url=http://web.mit.edu/krugman/www/ricardo.htm | author=Krugman, Paul|title=Ricardo's Difficult Idea |year=1996 |accessdate=2014-08-09}}</ref> insights in economics, Ricardo's theory implies that comparative advantage rather than [[absolute advantage]] is responsible for much of international trade. ==Classical theory and Ricardo's formulation== [[Adam Smith]] first alluded to the concept of ''absolute advantage'' as the basis for international trade in ''[[The Wealth of Nations]]'': {{Quote|text="If a foreign country can supply us with a commodity cheaper than we ourselves can make it, better buy it of them with some part of the produce of our own industry employed in a way in which we have some advantage. The general industry of the country, being always in proportion to the capital which employs it, will not thereby be diminished ... but only left to find out the way in which it can be employed with the greatest advantage."<ref>{{cite book|last1=Smith|first1=Adam|title=An Inquiry into the Nature and Causes of the Wealth of Nations|date=1776}}</ref>}} Writing several decades after Smith in 1808, [[Robert Torrens (economist)|Robert Torrens]] articulated a preliminary definition of comparative advantage as the loss from the closing of trade: {{Quote|text="[I]f I wish to know the extent of the advantage, which arises to England, from her giving France a hundred pounds of broad cloth, in exchange for a hundred pounds of lace, I take the quantity of lace which she has acquired by this transaction, and compare it with the quantity which she might, at the same expense of labour and capital, have acquired by manufacturing it at home. The lace that remains, beyond what the labour and capital employed on the cloth, might have fabricated at home, is the amount of the advantage which England derives from the exchange."<ref>{{cite book|last1=Torrens|first1=Lionel|title=The Economists Refuted and Other Early Economic Writings|year=1808|publisher=Kelley|location=New York|edition=1984|page=37}}</ref>}} [[Image:David ricardo.jpg|150px|right|thumb|David Ricardo]] In 1817, [[David Ricardo]] published what has since become known as the theory of comparative advantage in his book ''[[On the Principles of Political Economy and Taxation]]''. ===Ricardo's example=== [[File:Ricardo_example_of_comparative_advantage.svg|thumb|Graph illustrating Ricardo's example:<br />In case I (diamonds), each country spends 3600 hours to produce a mixture of cloth and wine.<br />In case II (squares), each country specializes in its comparative advantage, resulting in greater total output.]] In a famous example, Ricardo considers a [[world economy]] consisting of two countries, [[Portugal]] and [[England]], which produce two goods of identical quality. In Portugal, the ''a priori'' more efficient country, it is possible to produce [[wine]] and [[cloth]] with less labor than it would take to produce the same quantities in England. However, the relative costs of producing those two goods differ between the countries. {| class="wikitable" ! colspan="3" | '''Hours of work necessary to produce one unit''' |- ! {{diagonal split header|Country|Produce}} ! scope="col" | Cloth ! scope="col" | Wine |- ! scope="row" | '''England''' |100 |120 |- ! scope="row" | '''Portugal''' |90 |80 |} In this illustration, England could commit 100 hours of labor to produce one unit of cloth, or produce {{sfrac|5|6}} units of wine. Meanwhile, in comparison, Portugal could commit 90 hours of labor to produce one unit of cloth, or produce {{sfrac|9|8}} units of wine. So, Portugal possesses an ''absolute advantage'' in producing cloth due to fewer labor hours, and England has a ''comparative advantage'' due to lower opportunity cost. In the absence of trade, England requires 220 hours of work to both produce and consume one unit each of cloth and wine while Portugal requires 170 hours of work to produce and consume the same quantities. England is more efficient at producing cloth than wine, and Portugal is more efficient at producing wine than cloth. So, if each country specializes in the good for which it has a comparative advantage, then the global production of both goods increases, for England can spend 220 labor hours to produce 2.2 units of cloth while Portugal can spend 170 hours to produce 2.125 units of wine. Moreover, if both countries specialize in the above manner and England trades a unit of its cloth for {{sfrac|5|6}} to {{sfrac|9|8}} units of Portugal's wine, then both countries can consume at least a unit each of cloth and wine, with 0 to 0.2 units of cloth and 0 to 0.125 units of wine remaining in each respective country to be consumed or exported. Consequently, both England and Portugal can consume more wine and cloth under free trade than in [[autarky]]. ===Ricardian model=== The '''Ricardian model''' is a [[general equilibrium]] mathematical model of [[international trade]]. Although the idea of Ricardian model was first presented in the ''Essay on Profits'' (a single-commodity version) and then in the ''Principles'' (a multi-commodity version) by [[David Ricardo]], the first mathematical Ricardian model was published by [[William Whewell]] in 1833.<ref name="John Wood">{{cite book |title= David Ricardo: Critical Assessments|last= Wood |first= John Cunningham|year= 1991 |publisher= Taylor & Francis |location= |isbn= |page= 312 |url= https://books.google.com/books?hl=fr&lr=&id=h5GzUUfTL4sC&oi=fnd&pg=PA312&dq=Ricardian+model&ots=9IoNTNflKz&sig=EFXTd8Nvy83tKsyhn4tgouZJGWs#v=onepage&q=Ricardian%20model&f=false}}</ref> The earliest test of Ricardian model was performed by G.D.A MacDougall, which was published in ''Economic Journal'' of 1951 and 1952. <ref name="Barbara Ingham">{{cite book |title= International Economics: A European Focus|last= Ingham |first= Barbara|year= 2004 |publisher= Pearson Education |location= |isbn= |page= 22 |url= https://books.google.com/books?id=zIaS9R7HUGIC&printsec=frontcover&dq=international+economics&hl=fr&sa=X&ei=kkmdVbeBN6bnygPPy7OwCg&ved=0CCEQ6AEwAA#v=onepage&q=RIcardian%20model&f=false}}</ref> In Ricardian model, trade patterns depend on productivity differences. The following is a typical modern interpretation of the classical Ricardian model.<ref>{{cite book|last1=Krugman|first1=Paul|last2=Obstfeld|first2=Maurice|title=International Economics: Theory and Policy|year=1988|publisher=Prentice Hall|location=New York|pages=27–36|edition=2008}}</ref> In the interest of simplicity, it uses notation and definitions, such as opportunity cost, unavailable to Ricardo. The world economy consists of two countries, Home and Foreign, which produce wine and cloth. Labor, the only factor of production, is [[labor mobility|mobile]] domestically but not internationally; there may be migration between sectors but not between countries. We denote the labor force in Home by <math>\textstyle L</math>, the amount of labor required to produce one unit of wine in Home by <math>\textstyle a_{LW}</math>, and the amount of labor required to produce one unit of cloth in Home by <math>\textstyle a_{LC}</math>. The total amount of wine and cloth produced in Home are <math>Q_W</math> and <math>Q_C</math> respectively. We denote the same variables for Foreign by appending a [[prime (symbol)|prime]]. For instance, <math>\textstyle a'_{LW}</math> is the amount of labor needed to produce a unit of wine in Foreign. We don't know if Home is more productive than Foreign in making cloth. That is, if <math>a_{LC}<a'_{LC}</math>. Similarly, we don't know if Home has an absolute advantage in wine. However, we will assume that Home is more ''relatively'' productive in cloth than Foreign: :<math>a_{LC}/a'_{LC}<a_{LW}/a'_{LW}.</math> Equivalently, we may assume that Home has a comparative advantage in cloth in the sense that it has a lower opportunity cost for cloth in terms of wine than Foreign: :<math>a_{LC}/a_{LW}<a'_{LC}/a'_{LW}.</math> In the absence of trade, the relative price of cloth and wine in each country is determined solely by the relative labor cost of the goods. Hence the relative autarky price of cloth is <math>a_{LC}/a_{LW}</math> in Home and <math>a'_{LC}/a'_{LW}</math> in Foreign. With free trade, the price of cloth or wine in either country is the world price <math>P_C</math> or<math>P_W</math>. Instead of considering the world demand (or supply) for cloth and wine, we are interested in the world ''relative demand'' (or ''relative supply'') for cloth and wine, which we define as the ratio of the world demand (or supply) for cloth to the world demand (or supply) for wine. In general equilibrium, the world relative price <math>\textstyle P_C/P_W</math> will be determined uniquely by the intersection of world relative demand <math>\textstyle RD</math> and world relative supply <math>\textstyle RS</math> curves. [[File:World relative supply and demand in the classical Ricardo model of one-factor international trade between two countries.svg|thumb|The demand for cloth relative to wine decreases with the relative price of cloth in terms of wine; the supply <math>RS</math> of cloth relative to wine increases with relative price. Two relative demand curves <math>RD_1</math> and <math>RD_2</math> are drawn for illustrative purposes.]] We assume that the relative demand curve reflects substitution effects and is decreasing with respect to relative price. The behavior of the relative supply curve, however, warrants closer study. Recalling our original assumption that Home has a comparative advantage in cloth, we consider five possibilities for the relative quantity supplied at a given price. * If <math>\textstyle P_C/P_W = a_{LC}/a_{LW}<a'_{LC}/a'_{LW}</math>, then Foreign specializes in wine, for the wage <math>P'_W/a'_{LW}</math> in the wine sector is greater than the wage <math>P'_C/a'_{LC}</math> in the cloth sector. However, Home workers are indifferent between working in either sector. As a result, the quantity supplied can take any value. * If <math>\textstyle P_C/P_W < a_{LC}/a_{LW}<a'_{LC}/a'_{LW}</math>, then both Home and Foreign specialize in wine, for similar reasons as above, and so the quantity supplied is zero. * If <math>\textstyle a_{LC}/a_{LW}<P_C/P_W < a'_{LC}/a'_{LW}</math>, then Home specializes in cloth whereas Foreign specializes in wine. The quantity supplied is given by the ratio <math>\textstyle \frac{L/a_{LC}}{L'/a'_{LW}}</math> of the world production of cloth to the world production of wine. * If <math>\textstyle a_{LC}/a_{LW}<a'_{LC}/a'_{LW}<P_C/P_W</math>, then both Home and Foreign specialize in cloth. The quantity supplied tends to infinity as the quantity of wine supplied approaches zero. * If <math>\textstyle a_{LC}/a_{LW}<a'_{LC}/a'_{LW}=P_C/P_W</math>, then Home specializes in cloth while Foreign workers are indifferent between sectors. Again, the relative quantity supplied can take any value. [[File:Consumption possibilities in the classical Ricardo model of one-factor international trade between two countries.svg|thumb|The blue triangle depicts Home's original production (and consumption) possibilities. By trading, Home can also consume bundles in the pink triangle despite facing the same productions possibility frontier.]] As long as the relative demand is finite, the relative price is always bounded by the inequality :<math> a_{LC}/a_{LW}\leq {P_C/P_W}\leq {a'_{LC}/a'_{LW}}.</math> In autarky, Home faces a [[production possibilities frontier|production constraint]] of the form :<math> a_{LC}Q_C+a_{LW}Q_W\leq L,</math> from which it follows that Home's cloth consumption at the production possibilities frontier is :<math>Q_C=L/a_{LC}-(a_{LW}/a_{LC})Q_W</math>. With free trade, Home produces cloth exclusively, an amount of which it exports in exchange for wine at the prevailing rate. Thus Home's overall consumption is now subject to the constraint :<math>a_{LC}Q_C+a_{LC}(P_W/P_C)Q_W\leq L</math> while its cloth consumption at the ''consumption possibilities'' frontier is given by :<math>Q_C=L/a_{LC}-(P_W/P_C)Q_W\geq L/a_{LC}-(a_{LW}/a_{LC})Q_W</math>. A symmetric argument holds for Foreign. Therefore, by trading and specializing in a good for which it has a comparative advantage, each country can expand its consumption possibilities. Consumers can choose from bundles of wine and cloth that they could not have produced themselves in closed economies. === Terms of trade === Terms of trade is the rate at which one good could be traded for another. If both countries specialize in the good for which they have a comparative advantage then trade, the terms of trade for a good (that benefit both entities) will fall between each entities opportunity costs. In the example above one unit of cloth would trade for between <math>\frac 56</math> units of wine and <math>\frac 9 8</math> units of wine.<ref>{{Cite web|url=http://www.reviewecon.com/comparative-advantage.html|title=AP Economics Review: Comparative Advantage, Absolute Advantage, and Terms of Trade|last=|first=|date=2016-09-28|website=www.reviewecon.com/comparative-advantage.html|publisher=|access-date=}}</ref> ==Haberler's opportunity costs formulation== In 1930 Gottfried Haberler detached the doctrine of comparative advantage from Ricardo’s labor theory of value and provided a modern opportunity-cost formulation. Haberler’s reformulation of comparative advantage revolutionized the theory of international trade and laid the conceptual groundwork of modern trade theories. Haberler’s innovation was to reformulate the theory of comparative advantage such that the value of good X is measured in terms of the forgone units of production of good Y rather than the labor units necessary to produce good X, as in the Ricardian formulation. Haberler implemented this opportunity-cost formulation of comparative advantage by introducing the concept of a production possibility curve into international trade theory.<ref>{{cite journal|last1=Bernhofen|first1=Daniel|title=Gottfried haberler's 1930 reformulation of comparative advantage in retrospect|journal=Review of International Economics|date=2005|volume=13|issue=5|pages=997–1000|doi=10.1111/j.1467-9396.2005.00550.x}}</ref> ==Modern theories== Since 1817, economists have attempted to generalize the [[Ricardian model]] and derive the principle of comparative advantage in broader settings, most notably in the [[neoclassical economics|neoclassical]] ''specific factors'' [[Ricardo-Viner]] and ''factor proportions'' [[Heckscher–Ohlin model]]s. Subsequent developments in the [[new trade theory]], motivated in part by the empirical shortcomings of the H–O model and its inability to explain [[intra-industry trade]], have provided an explanation for aspects of trade that are not accounted for by comparative advantage.<ref>{{cite book|last1=Maneschi|first1=Andrea|title=Comparative Advantage in International Trade: A Historical Perspective|year=1998|publisher=Elgar|location=Cheltenham|pages=6–13}}</ref> Nonetheless, economists like [[Alan Deardorff]],<ref>{{cite journal|last1=Deardorff|first1=Alan|title=The General Validity of the Law of Comparative Advantage|journal=Journal of Political Economy|date=Oct 1980|volume=88|issue=5|pages=941–57|doi=10.1086/260915}}</ref> [[Avinash Dixit]], [[Gottfried Haberler]], and [[Victor D. Norman]]<ref>{{cite book|last1=Dixit|first1=Avinash|last2=Norman|first2=Victor|title=Theory of International Trade: A Dual, General Equilibrium Approach|year=1980|publisher=Cambridge University Press|location=Cambridge|pages=93–126}}</ref> have responded with weaker generalizations of the principle of comparative advantage, in which countries will only ''tend'' to export goods for which they have a comparative advantage. ===Dornbusch et al.'s continuum of goods formulation=== In both the Ricardian and H–O models, the comparative advantage theory is formulated for a 2 countries/2 commodities case. It can be extended to a 2 countries/many commodities case, or a many countries/2 commodities case. Adding commodities in order to have a smooth continuum of goods is the major insight of the seminal paper by Dornbusch, Fisher, and Samuelson. In fact, inserting an increasing number of goods into the chain of comparative advantage makes the gaps between the ratios of the labor requirements negligible, in which case the three types of equilibria around any good in the original model collapse to the same outcome. It notably allows for transportation costs to be incorporated, although the framework remains restricted to two countries.<ref>{{Cite journal | last1 = Dornbusch | first1 = R. | last2 = Fischer | first2 = S. | last3 = Samuelson | first3 = P. A. | year = 1977 | title = Comparative Advantage, Trade, and Payments in a Ricardian Model with a Continuum of Goods | journal = [[American Economic Review]] | volume = 67 | issue = 5 | pages = 823–39 | publisher = | jstor = 1828066 | url = | format = | accessdate = }}</ref><ref>{{Cite journal | doi = 10.2307/1885496| jstor = 1885496| title = Heckscher-Ohlin Trade Theory with a Continuum of Goods| journal = The Quarterly Journal of Economics| volume = 95| issue = 2| page = 203| date = 1980| last1 = Dornbusch | first1 = R. | last2 = Fischer | first2 = S. | last3 = Samuelson | first3 = P. A. }}</ref> But in the case with many countries (more than 3 countries) and many commodities (more than 3 commodities), the notion of comparative advantage requires a substantially more complex formulation.<ref>{{Cite journal | doi = 10.1111/j.1467-9396.2005.00552.x| title = How Robust is Comparative Advantage?| journal = Review of International Economics| volume = 13| issue = 5| pages = 1004–16| date = 2005| last1 = Deardorff | first1 = A. V.| url = https://deepblue.lib.umich.edu/bitstream/2027.42/73670/1/j.1467-9396.2005.00552.x.pdf}}</ref> ===Deardorff's general law of comparative advantage=== Skeptics of comparative advantage have underlined that its theoretical implications hardly hold when applied to individual commodities or pairs of commodities in a world of multiple commodities. Deardorff argues that the insights of comparative advantage remain valid if the theory is restated in terms of averages across all commodities. His models provide multiple insights on the correlations between vectors of trade and vectors with relative-autarky-price measures of comparative advantage. What has become to be known as the "Deardorff's general law of comparative advantage" is a model incorporating multiple goods, and which takes into account tariffs, transportation costs, and other obstacles to trade. ===Alternative approaches=== Recently, Y. Shiozawa succeeded in constructing a theory of international value in the tradition of Ricardo's [[cost-of-production theory of value]].<ref>Y. Shiozawa, A new construction of Ricardian trade theory / A many-country, many commodity case with intermediates goods and choice of production techniques, Evolutionary and Institutional Economics Review '''3'''(2): 141–87, 2007. Y. Shiozawa, A Final Solution of the Ricardo Problem on International Values, Iwanami Shoten, 2014.</ref> This was based on a wide range of assumptions: Many countries; Many commodities; Several production techniques for a product in a country; Input trade ([[International trade#Traded intermediate goods|intermediate goods]] are freely traded); Durable capital goods with constant efficiency during a predetermined lifetime; No transportation cost (extendable to positive cost cases). In a famous comment McKenzie pointed that "A moment's consideration will convince one that Lancashire would be unlikely to produce cotton cloth if the cotton had to be grown in England."<ref>L. W. McKenzie Specialization and Efficiency in World Production, Review of Economic Studies 21(3): 165–80. Citation from p.179.</ref> However, McKenzie and later researchers could not produce a general theory which includes traded input goods because of the mathematical difficulty.<ref>For the brief history of the theory of intermediates goods, see Appendix A: Previous Literature in A. Deardorff, Ricardian Comparative Advantage with Intermediate Inputs, The North American Journal of Economics and Finance '''16'''(1): 11–34, March 2005. http://fordschool.umich.edu/rsie/workingpapers/Papers501-525/r501.pdf</ref> As John Chipman points it, McKenzie found that "introduction of trade in intermediate product necessitates a fundamental alteration in classical analysis."<ref>Chipman, John S. (1965). "A Survey of the Theory of International Trade: Part 1, The Classical Theory". Econometrica 33 (3): 477–519. Section 1.8, p. 509.</ref> Durable capital goods such as machines and installations are inputs to the productions in the same title as part and ingredients. In view of the new theory, no physical criterion exists.<ref>Deardorff examines 10 versions of definitions in two groups but could not give a general formula for the case with intermdiate goods. A. Deardorff, Ricardian Comparative Advantage with Intermediate Inputs, The North American Journal of Economics and Finance '''16'''(1): 11–34, March 2005. See also http://fordschool.umich.edu/rsie/workingpapers/Papers501-525/r501.pdf See Appendix A: Previous Literature in particular.</ref> The competitive patterns are determined by the traders trials to find cheapest products in a world. The search of cheapest product is achieved by world optimal procurement. Thus the new theory explains how the global supply chains are formed.<ref>Y. Shiozawa (2016) The revival of classical theory of values, in Nobuharu Yokokawa et als. (Eds.) The Rejuvenation of Political Economy, May 2016, Oxon and New York: Routledge. Chapter 8, pp. 151–72. Y. Shiozawa, The New Interpretation of Ricardo's Four Magic Numbers and the New Theory of International Values / A Comment on Faccarello's "Comparative advantage"). A paper read on a conference on March 23, 2016.</ref> ==Empirical approach to comparative advantage== Comparative advantage is a theory about the benefits that specialization and trade would bring, rather than a strict prediction about actual behavior. (In practice, governments restrict international trade for a variety of reasons; under [[Ulysses S. Grant]], the US postponed opening up to free trade until its industries were up to strength, following the example set earlier by Britain.<ref>{{Cite journal|last=Chang|first=Ha-Joon|author-link=Ha-Joon Chang|date=December 2003|title=Kicking Away the Ladder: The "Real" History of Free Trade|url=|journal=FPIF Special Report|volume=|pages=|via=}}</ref>) Nonetheless there is a large amount of [[empirical evidence|empirical]] work testing the predictions of comparative advantage. The empirical works usually involve testing predictions of a particular model. For example, the Ricardian model predicts that technological differences in countries result in differences in labor productivity. The differences in labor productivity in turn determine the comparative advantages across different countries. Testing the Ricardian model for instance involves looking at the relationship between relative labor productivity and international trade patterns. A country that is relatively efficient in producing shoes tends to export shoes. ===Direct test: natural experiment of Japan=== Assessing the validity of comparative advantage on a global scale with the examples of contemporary economies is analytically challenging because of the multiple factors driving globalization: indeed, investment, migration, and technological change play a role in addition to trade. Even if we could isolate the workings of open trade from other processes, establishing its causal impact also remains complicated: it would require a comparison with a counterfactual world without open trade. Considering the durability of different aspects of globalization, it is hard to assess the sole impact of open trade on a particular economy. [[Daniel Bernhofen]] and John Brown have attempted to address this issue, by using a natural experiment of a sudden transition to open trade in a market economy. They focus on the case of Japan.<ref>{{cite journal|last1=Bernhofen|first1=Daniel|last2=Brown|first2=John|title=A Direct Test of the Theory of Comparative Advantage: The Case of Japan|journal=Journal of Political Economy|date=2004|volume=112|issue=1|pages=48–67|doi=10.1086/379944}}</ref><ref>{{cite journal|last1=Bernhofen|first1=Daniel|last2=Brown|first2=John|title=An Empirical Assessment of the Comparative Advantage Gains from Trade: Evidence from Japan|journal=American Economic Review|date=2005|volume=95|issue=1|pages=208–225.|doi=10.1257/0002828053828491}}</ref><ref>{{cite journal|last1=Bernhofen|first1=Daniel|last2=John|first2=Brown|title=Testing the General Validity of the Heckscher-Ohlin Theorem|journal=American Economic Journal: Microeconomics|date=2016|volume=8|issue=4|pages=54–90|doi=10.1257/mic.20130126}}</ref> ===Structural estimation=== Another important way of demonstrating the validity of comparative advantage has consisted in 'structural estimation' approaches. These approaches have built on the Ricardian formulation of two goods for two countries and subsequent models with many goods or many countries. The aim has been to reach a formulation accounting for both multiple goods and multiple countries, in order to reflect real-world conditions more accurately. Jonathan Eaton and Samuel Kortum underlined that a convincing model needed to incorporate the idea of a 'continuum of goods' developed by Dornbusch et al. for both goods and countries. They were able to do so by allowing for an arbitrary (integer) number i of countries, and dealing exclusively with unit labor requirements for each good (one for each point on the unit interval) in each country (of which there are i).<ref>{{cite journal|last1=Eaton|first1=Jonathan|last2=Kortum|first2=Samuel|title=Putting Ricardo to Work†|journal=Journal of Economic Perspectives|date=Spring 2012|volume=26|issue=2|pages=65–90|doi=10.1257/jep.26.2.65}}</ref> ===Earlier empirical work=== Two of the first tests of comparative advantage were by MacDougall (1951, 1952).<ref>{{cite news | author=MacDougall, G. D. A.| title=British and American exports: A study suggested by the theory of comparative costs. Part I.| journal=The Economic Journal| year=1951| volume=61 | issue=244|pages=697–724}}</ref><ref>{{cite news | author=MacDougall, G. D. A.| title=British and American exports: A study suggested by the theory of comparative costs. Part II.| journal=The Economic Journal| year=1952| volume=62 | issue=247|pages=487–521}}</ref> A prediction of a two-country Ricardian comparative advantage model is that countries will export goods where output per worker (i.e. productivity) is higher. That is, we expect a positive relationship between output per worker and number of exports. MacDougall tested this relationship with data from the US and UK, and did indeed find a positive relationship. The statistical test of this positive relationship was replicated<ref>{{cite news | author=Stern, Robert M.| title=British and American productivity and comparative costs in international trade| journal=Oxford Economic Papers |year=1962| pages=275–96.}}</ref><ref>{{cite news | author=Balassa, Bela. | title=An empirical demonstration of classical comparative cost theory| journal=The Review of Economics and Statistics|year=1963 |pages=231–238.}}</ref> with new data by Stern (1962) and Balassa (1963). Dosi et al. (1988)<ref>{{cite book | author=Dosi, G., Pavitt, K, & L. Soete | title=The Economics of Technical Change and International Trade | year=1988 | publisher=Brighton: Wheatsheaf }}</ref> conduct a book-length empirical examination that suggests that international trade in manufactured goods is largely driven by differences in national technological competencies. One critique of the textbook model of comparative advantage is that there are only two goods. The results of the model are robust to this assumption. Dornbusch et al. (1977)<ref>{{cite news |author1=Dornbusch, R. |author2=Fischer, S. |author3=P. Samuelson |last-author-amp=yes | title=Comparative Advantage, Trade and Payments in a Ricardian Model with a Continuum of Goods | journal=American Economic Review | volume=67 | year=1977 | pages=823–39 }}</ref> generalized the theory to allow for such a large number of goods as to form a smooth continuum. Based in part on these generalizations of the model, Davis (1995)<ref>{{cite news | author=Davis, D. | title=Intraindustry Trade: A Heckscher-Ohlin-Ricardo Approach | journal=Journal of International Economics | volume=39 | year=1995 | pages=201–26 | doi=10.1016/0022-1996(95)01383-3}}</ref> provides a more recent view of the Ricardian approach to explain trade between countries with similar resources. More recently, Golub and Hsieh (2000)<ref>{{cite news |author1=Golub, S. |author2=C-T Hsieh | title=Classical Ricardian Theory of Comparative Advantage Revisited | journal=Review of International Economics | volume=8 | issue=2 | year=2000 | pages=221–34 }}</ref> presents modern statistical analysis of the relationship between relative productivity and trade patterns, which finds reasonably strong correlations, and Nunn (2007)<ref>{{cite news | author=Nunn, N| title=Relationship-Specificity, Incomplete Contracts, and the Pattern of Trade| journal=Quarterly Journal of Economics | volume=122 | issue=2 | year=2007 |pages=569–600}}</ref> finds that countries that have greater enforcement of contracts specialize in goods that require relationship-specific investments. Taking a broader perspective, there has been work about the benefits of international trade. Zimring & Etkes (2014)<ref>Zimring, A. & Etkes, H. (2014) "When Trade Stops: Lessons from the 2007–2010 Gaza Blockade". ''Journal of International Economics'', forthcoming.</ref> finds that the [[Blockade of the Gaza Strip]], which substantially restricted the availability of imports to Gaza, saw labor productivity fall by 20% in three years. Markusen et al. (1994)<ref>{{cite book|author1=Markusen, J.R. |author2=Melvin J.R., Kaempfer |author3=W.M., K. Maskus |last-author-amp=yes | year=1994| title=International Trade: Theory and Evidence | url= http://www.colorado.edu/Economics/courses/Markusen/textbook/mmkm3.pdf |accessdate=2014-08-13 | page=218| publisher=McGraw-Hill | isbn=978-0070404472 }}</ref> reports the effects of moving away from [[autarky]] to [[free trade]] during the [[Meiji Restoration]], with the result that national income increased by up to 65% in 15 years. {{clear}} ==Considerations== ===Development economics=== The theory of comparative advantage, and the corollary that nations should specialize, is criticized on pragmatic grounds within the [[import substitution industrialization]] theory of [[development economics]], on empirical grounds by the [[Singer–Prebisch thesis]] which states that terms of trade between primary producers and manufactured goods deteriorate over time, and on theoretical grounds of [[infant industry]] and [[Keynesian economics]]. In older economic terms, comparative advantage has been opposed by [[mercantilism]] and [[economic nationalism]]. These argue instead that while a country may initially be comparatively disadvantaged in a given industry (such as Japanese cars in the 1950s), countries should shelter and invest in industries until they become globally competitive. Further, they argue that comparative advantage, as stated, is a static theory – it does not account for the possibility of advantage changing through investment or economic development, and thus does not provide guidance for long-term economic development. Much has been written since Ricardo as commerce has evolved and cross-border trade has become more complicated. Today trade policy tends to focus more on "[[competitive advantage]]" as opposed to "comparative advantage". One of the most in-depth research undertakings on "competitive advantage" was conducted in the 1980s as part of the [[Reagan administration]]'s [[Project Socrates]] to establish the foundation for a technology-based competitive strategy development system that could be used for guiding international trade policy. ==Criticism== Several arguments have been advanced against using comparative advantage as a justification for advocating free trade, and they have gained an audience among economists. For example, [[James Brander]] and [[Barbara Spencer]] demonstrated how, in a strategic setting where a few firms compete for the world market, export subsidies and import restrictions can keep foreign firms from competing with national firms, increasing welfare in the country implementing these so-called strategic trade policies.<ref>{{cite news |last=Krugman |first=Paul R. |title=Is Free Trade Passe? |journal=[[Journal of Economic Perspectives]] |year=1987 |volume=1 |issue=2 |pages=131–44}}</ref> However, the overwhelming consensus of the economics profession remains that while these arguments are theoretically valid under certain assumptions, these assumptions do not usually hold and should not be used to guide trade policy.<ref>{{cite news |last=Irwin |first=Douglas. |title=Retrospectives: Challenges to Free Trade |journal=[[Journal of Economic Perspectives]] |year=1991 |volume=5 |issue=2 |pages=201–08}}</ref> [[Gregory Mankiw]], chairman of the Harvard Economics Department, has said: ″Few propositions command as much consensus among professional economists as that open world trade increases economic growth and raises living standards.″<ref>{{cite web|url=http://gregmankiw.blogspot.com/2006/05/outsourcing-redux.html| author=Mankiw, N.G. |title=Outsourcing Redux|website= Greg Mankiw's Blog: Random Observations for Students of Economics|date=May 7, 2006}}</ref> Economist [[James K. Galbraith]] disputes these claims of the benefit of comparative advantage. He states that "free trade has attained the status of a god" and that ". . . none of the world's most successful trading regions, including Japan, Korea, Taiwan, and now mainland China, reached their current status by adopting [[neoliberal]] trading rules." He argues that ". . . comparative advantage is based upon the concept of [[constant returns]]: the idea that you can double or triple the output of any good simply by doubling or tripling the inputs. But this is not generally the case. For manufactured products, increasing returns, learning, and technical change are the rule, not the exception; the cost of production falls with experience. With increasing returns, the lowest cost will be incurred by the country that starts earliest and moves fastest on any particular line. Potential competitors have to protect their own industries if they wish them to survive long enough to achieve competitive scale."<ref>James K. Galbraith, The Predator State, Free Press, 2008, pp. 68–69</ref> Galbraith then explains that nations trapped into specializing in agriculture are condemned to perpetual poverty. Agriculture is dependent on a finite natural resource called land. People can't make more of it. As the population increases the per capita land resources decreases. Also the average farm size has also been increasing. If a nation is not allowed to expand into manufacturing and only specialize in agriculture, that nation is condemned to an ever expanding poverty.<ref>James K. Galbraith, The Predator State, Free Press, 2008, p. 70</ref> According to historian [[Cecil Woodham-Smith]], Ireland in the 1800s is an example of the dangers of specialization. When the union with Great Britain was formed in 1800, Irish textile industries protected by tariffs were exposed to world markets where England had a comparative advantage in technology, experience and scale of operation which devastated the Irish industry. Ireland was forced to specialize in the export of grain while the displaced Irish labor was forced into subsistence farming and relying on the potato for survival. When the potato blight occurred the resulting famine killed at least one million Irish in one of the worst famines in European history. As Woodham-Smith would later comment, "the Irish peasant was told to replace the potato by eating his grain, but [[Sir Charles Trevelyan, 1st Baronet|Trevelyan]] once again refused to take any steps to curb the export of food from Ireland. 'Do not encourage the idea of prohibiting exports,' he wrote, on September 3, (1846) 'perfect free trade is the right course'."<ref>[[Cecil Woodham-Smith]], ''[[The Great Hunger: Ireland 1845–1849]]'', 1962, pp. 49, 100, 118</ref> ==See also== {{Portal|Business and economics}} *[[Keynesian beauty contest]] * [[Bureau of Labor Statistics]] * [[Resource curse]] * [[Revealed comparative advantage]] ==References== {{reflist}} ==Bibliography== {{refbegin|30em}} * {{cite journal | last1 = Bernhofen | first1 = Daniel M | year = 2005 | title = Gottfried haberler's 1930 reformulation of comparative advantage in retrospect | url = | journal = Review of International Economics | volume = 13 | issue = 5| pages = 997–1000 | doi=10.1111/j.1467-9396.2005.00550.x}} * {{cite journal | last1 = Bernhofen | first1 = Daniel M. | last2 = Brown | first2 = John C. | year = 2004 | title = 'A Direct Test of the Theory of Comparative Advantage: The Case of Japan' | url = | journal = Journal of Political Economy | volume = 112 | issue = 1| pages = 48–67 | doi=10.1086/379944| citeseerx = 10.1.1.194.9649 }} * {{cite journal | last1 = Bernhofen | first1 = Daniel M. | last2 = Brown | first2 = John C. | year = 2005 | title = 'An Empirical Assessment of the Comparative Advantage Gains from Trade: Evidence from Japan' | url = | journal = American Economic Review | volume = 95 | issue = 1| pages = 208–25 | doi=10.1257/0002828053828491}} * {{cite journal | last1 = Bernhofen | first1 = Daniel M. | last2 = Brown | first2 = John C. | year = 2016 | title = 'Testing the General Validity of the Heckscher-Ohlin Theorem' | url = | journal = American Economic Journal: Microeconomics | volume = 8 | issue = 4| pages = 54–90 | doi=10.1257/mic.20130126}} * {{cite journal | last1 = Findlay | first1 = Ronald | year = 1987 | title = Comparative Advantage | url = | journal = The [[New Palgrave: A Dictionary of Economics]] | volume = 1 | issue = | pages = 514–17 }} * Markusen, Melvin, Kaempfer and Maskus, "International Trade: Theory and Evidence" * Hardwick, Khan and Langmead (1990). ''An Introduction to Modern Economics'' 3rd ed. * A. O'Sullivan & S.M. Sheffrin (2003). ''Economics. Principles & Tools''. {{refend}} ==External links== * [http://voxeu.org/content/cloth-wine-relevance-ricardo-s-comparative-advantage-21st-century "Cloth for Wine? The Relevance of Ricardo’s Comparative Advantage in the 21st Century" VoxEU Ebook.] * David Ricardo's [http://socserv2.socsci.mcmaster.ca/~econ/ugcm/3ll3/ricardo/prin/index.html The Principles of Trade and Taxation] (original source text)<!-- Broken (timeout) 20110228 Chealer --> * [http://web.mit.edu/krugman/www/ricardo.htm Ricardo's Difficult Idea], [[Paul Krugman]]'s 1996 exploration of why non-economists don't understand the idea of comparative advantage * [http://internationalecon.com/v1.0/ch40/ch40.html The Ricardian Model of Comparative Advantage] * [http://www.investopedia.com/ask/answers/09/law-comparative-advantage.asp What is comparative advantage? | Investopedia] * [http://www.investopedia.com/terms/c/comparativeadvantage.asp Comparative Advantage Definition | Investopedia] {{Trade|state=expanded}} {{DEFAULTSORT:Comparative Advantage}} [[Category:Microeconomic theories]] [[Category:Classical economics]] [[Category:International trade]] [[Category:Economics comparisons]]'