International trade is in principle not different from domestic trade as the motivation and the behavior of parties involved in a trade does not change fundamentally depending on whether trade is across a border or not. The main difference is that international trade is typically more costly than domestic trade. The reason is that a border typically imposes additional costs such as tariffs, time costs due to border delays and costs associated with country differences such as language, the legal system or a different culture.

Models

Several different models have been proposed to predict patterns of trade and to analyze the effects of trade policies such as tariffs.

Ricardian model

main: Ricardian model

The Ricardian model focuses on comparative advantage and is perhaps the most important concept in international trade theory. In a Ricardian model, countries specialize in producing what they produce best. Unlike other models, the Ricardian framework predicts that countries will fully specialize instead of producing a broad array of goods. Also, the Ricardian model does not directly consider factor endowments, such as the relative amounts of labor and capital within a country.

Heckscher-Ohlin model

main: Heckscher-Ohlin model The Heckscher-Ohlin model was produced as an alternative to the Ricardian model of basic comparative advantage. Despite its greater complexity it did not prove much more accurate in its predictions. However from a theoretical point of view it did provide an elegant solution by incorporating the neoclassical price mechanism into international trade theory.

The theory argues that the pattern of international trade is determined by differences in factor endowments. It predicts that countries will export those goods that make intensive use of locally abundant factors and will import goods that make intensive use of factors that are locally scarce. Empirical problems with the H-O model, known as the Leontief paradox, were exposed in empirical tests by Wassily Leontief who found that the United States tended to export labor intensive goods despite having a capital abundance.

Specific factors model

In this model, labour mobility between industries is possible while capital is immobile between industries in the short-run. Thus, this model can be interpreted as a 'short run' version of the Heckscher-Ohlin model. The specific factors name refers to the given that in the short-run specific factors of production, such as physical capital, are not easily transferable between industries. The theory suggests that if there is an increase in the price of a good, the owners of the factor of production specific to that good will profit in real terms. Additionally, owners of opposing specific factors of production (i.e. labour and capital) are likely to have opposing agendas when lobbying for controls over immigration of labour. Conversely, both owners of capital and labour profit in real terms from an increase in the capital endowment. This model is ideal for particular industries. This model is ideal for understanding income distribution but awkward for discussing the pattern of trade.