The Heckscher–Ohlin model (, H–O model) is a general equilibrium mathematical model of international trade, developed by Eli Heckscher and Bertil Ohlin at the Stockholm School of Economics. It builds on David Ricardo's theory of comparative advantage by predicting patterns of commerce and production based on the resources of a trading region. The model essentially says that countries export the products which use their relatively abundant and cheap factors of production, and import the products which use the countries' relatively scarce factors.
Features of the model Relative endowments of the factors of production (land, labor, and capital) determine a country's comparative advantage. Countries have comparative advantages in those goods for which the required factors of production are relatively abundant locally. This is because the profitability of goods is determined by input costs. Goods that require locally abundant inputs are cheaper to produce than those goods that require locally scarce inputs.
For example, a country where capital and land are abundant but labor is scarce has a comparative advantage in goods that require lots of capital and land, but little labor — such as grains. If capital and land are abundant, their prices are low. As they are the main factors in the production of grain, the price of grain is also low—and thus attractive for both local consumption and export. Labor-intensive goods, on the other hand, are very expensive to produce since labor is scarce and its price is high. Therefore, the country is better off importing those goods.
The comparative advantage is due to the fact that nations have various factors of production, the endowment of factors is the number of resources such as land, labor, and capital that a country has. Countries are endowed with multiple factors which explains the difference in the costs of a particular factor when a cheaper factor is more abundant. The theory predicts that nations will export the goods that make the most of the factors that are abundant in their soil and will import those that are made with scarce factors. Thus, this theory aims to explain the scheme of international trade that we observe in the world economy. Ohlin and Heckscher's theory advocates that the pattern of international trade is determined by differences in factor endowments rather than by differences in productivity. The endowments are relative and not absolute. One nation may have more land and workers than another but be relatively abundant in one of two factors. For example; The United States is a leading exporter of agricultural products, which reflects its great abundance of arable land, and on the other hand, China excels in the export of goods made with cheap labor such as textiles or shoes. This demonstrates why the United States has been a large importer of these Chinese products since it does not abound in cheap labor.
Theoretical development While still building on traditional models such as the Ricardian framework, the mid 1900s bring forth innovation in international trade theory with the introduction of the Heckscher-Ohlin (H-O) model, developed by Swedish economists Eli Heckscher and Bertil Ohlin from the Stockholm School of Economics. The H-O model advances international trade theory by introducing the concept of factor endowments within a country as well as the underlying causes for differences in comparative costs between countries, while assuming countries will have identical production technologies. The H-O framework finds that countries have differing comparative costs even though they have the same production technologies due to differences in factors of production, such as the geographical abundance of natural resources or population size. Furthermore, what the H-O model concludes is that traded commodities are essentially bundles of factors (land, labor, and capital) and therefore the international trade of commodities is indirect factor arbitrage (Leamer 1995).The H-O model more accurately describes international trade patterns in modern times (post WWII) due to the increased ability of transferring knowledge/ production technologies between countries, mainly focusing on factorial differences such as labor force and resource allocation as to why countries trade with each other. The Ricardian model of comparative advantage has trade ultimately motivated by differences in labour productivity using different "technologies". Heckscher and Ohlin did not require production technology to vary between countries, so (in the interests of simplicity) the "H–O model has identical production technology everywhere". Ricardo considered a single factor of production (labour) and would not have been able to produce comparative advantage without technological differences between countries (all nations would become autarkic at various stages of growth, with no reason to trade with each other). The H–O model removed technology variations but introduced variable capital endowments, recreating endogenously the inter-country variation of labour productivity that Ricardo had imposed exogenously. With international variations in the capital endowment like infrastructure and goods requiring different factor "proportions", Ricardo's comparative advantage emerges as a profit-maximizing solution of capitalist's choices from within the model's equations. The decision that capital owners are faced with is between investments in differing production technologies; the H–O model assumes capital is privately held.
Original publication
Bertil Ohlin first explained the theory in a book published in 1933. Ohlin wrote the book alone, but he credited Heckscher as co-developer of the model because of his earlier work on the problem, and because many of the ideas in the final model came from Ohlin's doctoral thesis, supervised by Heckscher.
Interregional and International Trade itself was verbose, rather than being pared down to the mathematical, and appealed because of its new insights.
2×2×2 model
The original H–O model assumed that the only difference between countries was the relative abundances of labour and capital. The original Heckscher–Ohlin model contained two countries, and had two commodities that could be produced. Since there are two (homogeneous) factors of production this model is sometimes called the "2×2×2 model".
The model has "variable factor proportions" between countries—highly developed countries have a comparatively high capital-to-labor ratio compared to developing countries. This makes the developed country capital-abundant relative to the developing country, and the developing nation labor-abundant in relation to the developed country.
With this single difference, Ohlin was able to discuss the new mechanism of comparative advantage, using just two goods and two technologies to produce them. One technology would be a capital-intensive industry, the other a labor-intensive business—see "assumptions" below.
Extensions
The model has been extended since the 1930s by many economists. These developments did not change the fundamental role of variable factor proportions in driving international trade, but added to the model various real-world considerations (such as tariffs) in the hopes of increasing the model's predictive power, or as a mathematical way of discussing macroeconomic policy options.
Notable contributions came from Paul Samuelson, Ronald Jones, and Jaroslav Vanek, so that variations of the model are sometimes called the Heckscher–Ohlin–Samuelson model (HOS) or the Heckscher–Ohlin–Vanek model in the neo-classical economics.
Theoretical assumptions
The original, 2×2×2 model was derived with restrictive assumptions, partly for the sake of mathematical simplicity. Some of these have been relaxed for the sake of development. These assumptions and developments are listed here.
Both countries have identical production technology
This assumption means that producing the same output of either commodity could be done with the same level of capital and labour in either country. Actually, it would be inefficient to use the same balance in either country (because of the relative availability of either input factor) but, in principle this would be possible. Another way of saying this is that the per-capita productivity is the same in both countries in the same technology with identical amounts of capital.
Countries have natural advantages in the production of various commodities in relation to one another, so this is an "unrealistic" simplification designed to highlight the effect of variable factors. This meant that the original H–O model produced an alternative explanation for free trade to Ricardo's, rather than a complementary one; in reality, both effects may occur due to differences in technology and factor abundances.
In addition to natural advantages in the production of one sort of output over another (wine vs. rice, say) the infrastructure, education, culture, and "know-how" of countries differ so dramatically that the idea of identical technologies is a theoretical notion. Ohlin said that the H–O model was a long-run model, and that the conditions of industrial production are "everywhere the same" in the long run.
Production output is assumed to exhibit constant returns to scale In a simple model, both countries produce two commodities. Each commodity in turn is made using two factors of production. The production of each commodity requires input from both factors of production—capital (K) and labor (L). The technologies of each commodity is assumed to exhibit constant returns to scale (CRS). CRS technologies implies that when inputs of both capital and labor is multiplied by a factor of k, the output also multiplies by a factor of k. For example, if both capital and labor inputs are doubled, output of the commodities is doubled. In other terms the production function of both commodities is "homogeneous of degree 1".
The assumption of constant returns to scale CRS is useful because it exhibits a diminishing returns in a factor. Under constant returns to scale, doubling both capital and labor leads to a doubling of the output. Since outputs are increasing in both factors of production, doubling capital while holding labor constant leads to less than doubling of an output. Diminishing returns to capital and diminishing returns to labor are crucial to the Stolper–Samuelson theorem.
The technologies used to produce the two commodities differ
The CRS production functions must differ to make trade worthwhile in this model. For instance if the functions are Cobb–Douglas technologies the parameters applied to the inputs must vary. An example would be:
Arable industry: Fishing industry:
where A is the output in arable production, F is the output in fish production, and K, L are capital and labor in both cases.
In this example, the marginal return to an extra unit of capital is higher in the fishing industry, assuming units of fish (F) and arable output (A) have equal value. The more capital-abundant country may gain by developing its fishing fleet at the expense of its arable farms. Conversely, the workers available in the relatively labor-abundant country can be employed relatively more efficiently in arable farming.
Factor mobility within countries Within countries, capital and labor can be reinvested and reemployed to produce different outputs. Similar to Ricardo's comparative advantage argument, this is assumed to happen without cost. If the two production technologies are the arable industry and the fishing industry it is assumed that farmers can shift to work as fishermen with no cost and vice versa.