本文是經(jīng)濟學(xué)專業(yè)的Essay范例,題目是“Assumptions of the H-O Model(H-O模型的假設(shè))”,Eli Heckscher(1919)和Bertil Ohlin(1933)通過強調(diào)國家要素稟賦的構(gòu)成與商品貿(mào)易模式之間的關(guān)系,為國際貿(mào)易的重要和實質(zhì)性的理論發(fā)展奠定了基礎(chǔ)。Heckscher-Ohlin (H-O)理論是解釋為什么國家與其他國家進行商品和服務(wù)貿(mào)易的最簡單的理論。Heckscher-Ohlin模型是國際貿(mào)易理論的一般均衡數(shù)學(xué)模型,它建立在李嘉圖比較優(yōu)勢理論的基礎(chǔ)上,基于國家的要素稟賦對貿(mào)易格局和商品生產(chǎn)進行預(yù)測(Learner 1995)。
Introduction介紹
Eli Heckscher (1919) and Bertil Ohlin (1933) found the basis for crucial and substantial theoretical developments of international trade by emphasizing the relationships between the composition of countries’ factor endowments and commodity trade patterns. The Heckscher-Ohlin (H-O) theory is the simplest explanation for why countries involve in trade of goods and services with other countries. Heckscher-Ohlin model, which is the general equilibrium mathematical model of international trade theory, is built on the Ricardian theory of comparative advantage by making prediction on trade patterns and production of goods based on the factor endowments of nations (Learner 1995).
Assumptions of the Heckscher-Ohlin Model
The following assumptions pertain to the 2*2 model of Heckscher-Ohlin.
It is assumed that there are only two nations (1 and 2) with two goods for trade (X and Y) and two factors of production (capital and labour).
For producing the goods, both nations use the same technology and they use uniform factors of production.
In both countries, good X is labour intensive and Y is capital intensive.
The tastes and preferences of both nations are the same (both countries can be represented in the same indifference curve).
In both nations, the assumption of constant returns to scale is applicable for the production of goods X and Y.
In both nations, specialization in production is not complete.
Goods and factor markets in both nations are perfectly competitive.
There exists perfect mobility of factors of production within each country though international mobility is not possible.
There are no restrictions or limitations to the free flow of international trade. That is, there exist no transportation costs, tariffs, or like other obstructions either to control or to restrict the exports or imports.
It is assumed that there exists full employment of all resources in both nations. That is, there will not be any under employed resource in either nation.
The exports and imports between the nations are balanced. It means that the total value of the exports will be equal to the total value of imports in both nations.
Implications of the Assumptions
The assumptions are made in order to depict the theory in a two-dimensional figure. It is also implied that both countries have access to and use the same general production techniques. The labour-capital ratio (L/K) of commodity X is higher than that of Y in both countries with the same relative prices of factors. As constant returns to scale is assumed, increase in the amount of labour and capital will result in the proportionate increase in the output also. Another implication is that though free international trade exists, both of the countries produce both commodities and it can be presumed that both countries are not small in size.
As the tastes and preferences related to demand are identical in both countries, if the relative prices of the goods are equal, the consumption of goods X and Y will be in the same proportion in both countries. Likewise, in both countries producers, traders and consumers are too small to affect the commodity prices. Mobility of factors of production implies that capital and labour are free to move from areas or industries of lower prices (earnings) to those of higher prices (earnings) until earnings become same equal in all areas or industries. That is, price equalization theory is implied here. International differences in the earnings exist because of the factor immobility in the absence of international trade.
由于兩國與需求相關(guān)的品味和偏好是相同的,如果商品的相對價格相等,那么兩國對商品X和Y的消費比例將相同。同樣,在這兩個國家,生產(chǎn)者、貿(mào)易商和消費者的規(guī)模都太小,不足以影響大宗商品價格。生產(chǎn)要素的流動性意味著資本和勞動力可以自由地從價格較低(收入)的地區(qū)或行業(yè)轉(zhuǎn)移到價格較高(收入)的地區(qū)或行業(yè),直到所有地區(qū)或行業(yè)的收入相等為止。也就是說,這里隱含了價格均衡理論。在沒有國際貿(mào)易的情況下,由于要素的不流動性,在收入方面存在國際差異。
The assumption of incomplete production specialization implies that the process of specialization in production continues until the commodity prices (either relative or absolute) prices are the same in both countries. Again, if the transportation costs, tariffs or any other restriction are allowed, specialization will continue only until price differences by less than or equal to the costs or tariffs.
The Heckscher-Ohlin ModelHeckscher-Ohlin模型
Heckscher-Ohlin model is generally described as two countries, two goods and two factors model (2x2x2 model). This formulation of HO model was mathematically developed by Paul Samuelson. The goal of the model is to predict the pattern of international trade in commodities between the two countries on the basis of differences in factor endowments in both the countries.
Heckscher-Ohlin模型一般被描述為兩個國家、兩個商品和兩個因素模型(2x2x2模型)。這種HO模型的表述是由Paul Samuelson在數(shù)學(xué)上提出的。該模型的目標是在兩國要素稟賦差異的基礎(chǔ)上預(yù)測兩國之間的國際商品貿(mào)易格局。
Definition: A nation exports the commodities which are produced out of its relatively abundant and cheap factors or resources and imports the commodity which is produced out of relatively scarce factors or resources. In another words, relatively labour abundant country exports relatively labour intensive commodity and imports the relatively capital-intensive commodity. Country 1 exports commodity X because X is the Labor (L) intensive commodity and L is relatively cheap and abundant factor in country 1. Country 2 exports commodity Y because Y is the Capital (K) intensive commodity and K is relatively cheap and abundant factor in country 2.
The theory implicates two things: first, different supply conditions in terms of resource endowments explain comparative advantage and second, countries export goods that use abundant and cheap factors of production and import goods that use scarce and expensive factors.
According to Heckscher-Ohlin theory, international and interregional differences in production costs occur due to the differences in the supply of factors of production. Under free trade, countries export the commodities whose production requires intensive use of abundant factors and import the commodities whose production requires the scarce factors. Hence, international trade compensates for the uneven geographic distribution of factors of production. The theory gives insight to the fact that commodities are the bundles of factors (land, labour and capital). Thus, the exchange of commodities is indirect arbitrage of factors of production and the transfer of services of otherwise immobile factors from regions where factors are abundant to regions where they are scarce.
The H-O theorem identifies the basic reason for comparative advantage and international trade as the different factor abundance or factor endowments among nations. Because of this particular reason, the theory is known as factor proportions or factor endowment theory. The theory postulates that the difference in relative factor endowment and prices is the main reason for the difference in relative commodity prices between two countries.
H-O定理將比較優(yōu)勢和國際貿(mào)易產(chǎn)生的根本原因確定為各國要素豐度或要素稟賦的不同。由于這個特殊的原因,該理論被稱為要素比例理論或要素稟賦理論。該理論假設(shè)相對要素稟賦和價格的差異是造成兩國相對商品價格差異的主要原因。
Factor Endowments
Factor endowment can be defined as the ratio of capital to labour (K/L). If the capital – labour ratio in country 1 is greater than in country 2, then country 1 is said to be relatively capital-abundant (and labour-scarce) while country 2 is labour abundant (and capital scarce). Symbolically, this can be represented as:(K/L) 1 > (K/L) 2
Important implication of different factor endowments is for autarky prices of factors of production (the autarky prices are implied in the figure represented below).
For two countries with same demand patterns, relative factor prices leads to relative factor scarcities. Country 2 will have relatively inexpensive labour and country 1 is in a position to provide relatively inexpensive (abundant) capital.
Factor Intensities, Factor Abundance and Production Frontiers under H-O Model
Factor Intensity
Commodity Y is said to be relative capital intensive and commodity X is relatively labour intensive if the capital labour ratio used in the production of Y is higher than that of the production of commodity X.
That is,(K/L) y > (K/L) x
If the for the production of commodity Y, the country use 2K and 2L, then K/L = 1 and if the production of commodity X requires 1K and 4L, K/L=1/4. In this case, it can be said that commodity Y is capital intensity and commodity X is labour intensive. Factor intensity depends on K/L rather than the absolute amount of K and L.
At the equilibrium points, for producing the commodities, both countries choose capital-labour ration that minimize the factor costs at the prevailing relative factor prices.
The relative factor prices are represented as W=w/r where w is the price of labour and r is the price of capital. Though in principle, the factor intensities can be reversed when factor prices change. But it is assumed that this does not exist in H-O model. There is no factor intensity reversal.
Factor Abundance
Factor abundance can be defined in terms of two ways:1) Physical Units and 2) Relative Prices of factors.
In terms of physical units, the overall amount of capital and labour available to each country is taken into consideration (that is, TK and TL). As per this definition, country 2 is capital abundant if the ratio of total amount of capital (TK) to total amount of labour available in country 2 will be greater than that in country 1. The ratio of TK/TL is important rather than total absolute amount of K and L of the countries.
就實物單位而言,考慮到每個國家可用的資本和勞動力總額(即傳統(tǒng)文化和傳統(tǒng)文化)。根據(jù)這一定義,如果國家2的資本總額(TK)與可用勞動力總額的比率大于國家1,則國家2是資本充裕的。重要的是TK/TL的比例,而不是K和L的絕對總量。
Country 2 may have less capital than country 2 and still there may be the capital abundant country if TK/TL in country 2 exceeds TK/TL in country 1.
In terms of relative factor prices, country 2 is capital abundant if PK/PL is lower in country 2 than in country 1. As the price of capital is taken to be the interest rate, r and the price of labour is wage, w, then PK/PL= r/w. The ratio of r/w is important, not the absolute level of r or w, in determining whether a country is capital abundant or labour abundant. The first definition takes only the supply of factors into consideration, while the second considers both supply and demand factors.
Factor Endowments and Production Frontiers
When country 2 is capital abundant and the commodity Y is capital intensive, country 2 can produce relatively more of commodity Y than in country 1. Similarly, if country 1 is labour abundant and commodity X is labour intensive, country 1 can produce relatively more of commodity X than country 2. This situation gives a relatively flatter and wider production frontier curve for country 1 than country 2.
Diagrammatic Representation of H-O Model
The following figure represents the Heckscher-Ohlin model diagrammatically. As it is assumed, two countries have same tastes and preferences for demand, both the countries are represented in the same indifference map.
I is the highest indifference curve that country 1 and country 2 can achieve separately in the absence of international trade. The points A and A/ represent equality of production and consumption of both countries in the absence of trade. The tangency points of A and A/ determine the no-trade equilibrium prices of PA and PA/ in country 1 and country 2 respectively.
I是國家1和國家2在沒有國際貿(mào)易的情況下分別能達到的最高的無差異曲線。A和A/代表兩國在沒有貿(mào)易的情況下生產(chǎn)和消費的平等。A和A/的切點分別決定了PA和PA/在國家1和國家2的非貿(mào)易均衡價格。
When PA < PA/, country 1 has comparative advantage in the production of commodity X and country 2 has comparative advantage in commodity Y.
The right side of the figure shows that country 1 specializes in commodity X and Country 2 in commodity Y when both countries involve in international trade.
Specialization proceeds at point where country 1 achieves the point B and country 2 reaches at point B/. At these points transformation curves are tangent to the common relative price line of PB.
Country 1 exports commodity X in exchange for commodity Y and consumes at point E on the second indifference curve (IC II). Likewise, country 2 exports commodity Y in exchange for commodity X and the relative equilibrium point of country 2 is point E/ which coincides with point E.
In this context, it is important to note that country 1’s exports of commodity X equal country 2’s imports of commodity X (that is, BC=C/B/). Similarly, country 2’s exports of commodity Y equal country 1’s imports of commodity Y (that is, B/C/= CE).
When PX/PY>PB, country 1 wants to export more of commodity X than country 2 is able to import at this high relative price, and PX/PY tends to diminish to PB, which is equilibrium and normal price. Likewise, when PX/PY< PB, country 1 is in a position to export less of commodity X than country 2 desires to import at this low relative price and gradually, PX/PY tends to rise towards PB.
當PX/PY>PB時,國家1想要出口比國家2能進口更多的商品X,而PX/PY趨于PB,這是均衡正常價格。同樣,當PX/PY< PB時,國家1出口的X商品比國家2在這個較低的相對價格下進口的要少,PX/PY逐漸向PB上升。
At point E, more of commodity Y and less of commodity X than at the point A are involved. However, country 1 will gain from international trade because E lies on higher indifference curve (IC II). Similarly, though at E/ more commodity of X and less commodity of Y are involved compared to the point of A/, country 2 gains from the trade because E/ lies on higher indifference curve, IC II.
Prepositions of H-O theorem and other empirical Studies
As a connotation of H-O theorem, three other prepositions or theorems are associated:
Factor price equalization theorem 2) Stopler-Samuelson theorem and 3) the Rybcsynski Theorem (Jone 2002).
The Factor Price Equalization Theorem要素價格均衡定理
Even though the national frontiers rule out the international mobility of factors, free trade in commodities leads to reduce the disparities in demand relative to supply of factor and thus to decrease the disparities in factor returns among different countries. International free trade leads to sharing of same technology by different countries and bringing of equality of factor returns if the factor endowments are similar and sufficient quantity of commodities are produced commonly (Samuelson 1992).
雖然國家邊界排除了要素的國際流動,但商品的自由貿(mào)易導(dǎo)致減少要素的需求相對于供應(yīng)的差距,從而減少不同國家間要素回報的差距。如果要素稟賦相似,共同生產(chǎn)足夠數(shù)量的商品,國際自由貿(mào)易就會導(dǎo)致不同國家共享相同的技術(shù),帶來同等的要素收益(Samuelson 1992)。
The Stolper- Samuelson Theorem
Changes in relative commodity prices as brought by free international trade have strong effects on the factor prices or rewards. If there is no joint production, some factors may raise their rewards uncontrollably and other rewards may be lowered unambiguously. If the number of factors equals the number of commodities and production is non-joint, the relative changes in commodity prices will raise the price of any particular factor (Uekawa, 1971).
The Rybczynski Theorem
If there is unbalanced growth in factor supplies, it may lead to stronger asymmetric changes in outputs also. If the quantity of factors of production and commodities are evenly matched and production is non-joint, this pattern of asymmetry may pertain to growth in some factors of production (if there is given commodity prices) and may lead to the reduction of outputs.
Empirical Legitimacy and Leontief’s Investigation實證合法性與里昂蒂夫的調(diào)查
Leontief (1953) was the first to confront the Heckscher-Ohlin model with empirical investigation. He had developed a set of data in the frame of input-output accounts for the U.S economy and he computed the amounts of labour and capital used in each industry for 1947. Likewise, he made use of U S trade data for the same year to compute the factors of production (labour and capital) used in the production of $1 million of US exports and imports.
Leontief(1953)是第一個用實證研究對抗Heckscher-Ohlin模型的人。他在美國經(jīng)濟的投入產(chǎn)出核算框架內(nèi)開發(fā)了一套數(shù)據(jù),并計算了1947年各個行業(yè)的勞動力和資本使用量。同樣,他利用同年的美國貿(mào)易數(shù)據(jù)來計算生產(chǎn)要素(勞動力和資本)用于生產(chǎn)100萬美元的美國出口和進口。
Each column of the table shows the amount of labour and capital required to occur $1 million worth of international trade (exports or imports) to United States in the year 1947.
Firstly Leontief measured the capital and labour required for the exports from US. This estimation required the labour and capital used in each and every exporting industry and from the first row of the table, it is seen that $2.5 worth of capital was used to export worth of $1million. For labour, 182 person-years were used to produce the same exports.
Taking the ratio of labour and capital, it can be said as in the third row of the table, each labourer is working with $13,700 worth of capital. Turning to the import side of the calculation, there emerged a problem non-availability of data on foreign technology. Still Leontif managed to estimate the model assuming that same technology of US used in imports. The estimation on imports (i.e., $3.1 million of capital, 170 person- years and capital-labour ratio as $18,000) indicates that capital labour ratio of imports is higher than that of US exports. But US economy is found in 1956 as capital-abundant and this appears to contradict the H-O theorem. Thus the findings of Leontief came to be called as “Leontief Paradox” (Learner 1995).
以勞動力和資本的比率為例,我們可以在表格的第三排看到,每個勞動者都有價值13700美元的資本。在計算的進口方面,出現(xiàn)了一個問題,即無法獲得有關(guān)外國技術(shù)的數(shù)據(jù)。盡管如此,萊昂提夫還是成功地估算出了這個模型,前提是美國在進口中使用了同樣的技術(shù)。對進口的估計(即310萬美元的資本,170人-年,資本勞動比為18,000美元)表明,進口的資本勞動比高于美國出口的資本勞動比。但1956年的美國經(jīng)濟是資本充裕的,這似乎與H-O定理相矛盾。因此Leontief的發(fā)現(xiàn)被稱為“Leontief悖論”(Learner 1995)。
Under the framework of H-O theorem, many explanations have been proposed for the existence of this paradox.
U S and foreign technologies are not same unlike the assumption of H-O theorem.
The year 1947 was not usual year as World War II has just ended
As H-O model assumes, the U S was not engaged in free trade.
Other Empirical Estimations of H-O model
By examining the limitations of Leontief ‘s estimation, Bowen, Leamer and Sveikauskas (1987) estimated the H-O model by using data on a large number of countries. It was estimated to check whether countries are net exporters of the factors of production (which are relatively abundant) as factors of production are indirectly embodied in the trade. Cline (1997) suggested a more generalized H-O model by taking into account more and disaggregated factors of production. It was recognized that factor endowments change over a period of time as the investment and technological advances occur.
Concluding Remarks
H-O theorem has been vehemently criticized on many grounds including in terms of its basic assumptions. Some empirical studies even questioned the validity of the theory. Despite of the many criticisms and drawbacks, H-O theory has its own merits and contributions in the theoretical history of international trade.
H-O定理在許多方面受到了激烈的批評,包括其基本假設(shè)。一些實證研究甚至質(zhì)疑該理論的有效性。盡管存在許多批評和缺陷,但H-O理論在國際貿(mào)易理論史上有其自身的優(yōu)點和貢獻。
By taking both commodity and factor prices into consideration, H-O theory provides a more and satisfactory explanation of international trade.
通過同時考慮商品價格和要素價格,H-O理論為國際貿(mào)易提供了更令人滿意的解釋。
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