What Is International Trade Theory?

Read this introduction to mercantilism and the difference between classical country-based theories and modern firm-based theories. What is the historical significance of mercantilism for international trade patterns?

2.1 What Is International Trade Theory?

Porter's National Competitive Advantage Theory

In the continuing evolution of international trade theories, Michael Porter of Harvard Business School developed a new model to explain national competitive advantage in 1990. Porter's theory stated that a nation's competitiveness in an industry depends on the capacity of the industry to innovate and upgrade. His theory focused on explaining why some nations are more competitive in certain industries. To explain his theory, Porter identified four determinants that he linked together. The four determinants are (1) local market resources and capabilities, (2) local market demand conditions, (3) local suppliers and complementary industries, and (4) local firm characteristics.


  1. Local market resources and capabilities (factor conditions). Porter recognized the value of the factor proportions theory, which considers a nation's resources (e.g., natural resources and available labor) as key factors in determining what products a country will import or export. Porter added to these basic factors a new list of advanced factors, which he defined as skilled labor, investments in education, technology, and infrastructure. He perceived these advanced factors as providing a country with a sustainable competitive advantage.
  2. Local market demand conditions. Porter believed that a sophisticated home market is critical to ensuring ongoing innovation, thereby creating a sustainable competitive advantage. Companies whose domestic markets are sophisticated, trendsetting, and demanding forces continuous innovation and the development of new products and technologies. Many sources credit the demanding US consumer with forcing US software companies to continuously innovate, thus creating a sustainable competitive advantage in software products and services.
  3. Local suppliers and complementary industries. To remain competitive, large global firms benefit from having strong, efficient supporting and related industries to provide the inputs required by the industry. Certain industries cluster geographically, which provides efficiencies and productivity.
  4. Local firm characteristics. Local firm characteristics include firm strategy, industry structure, and industry rivalry. Local strategy affects a firm's competitiveness. A healthy level of rivalry between local firms will spur innovation and competitiveness.

In addition to the four determinants of the diamond, Porter also noted that government and chance play a part in the national competitiveness of industries. Governments can, by their actions and policies, increase the competitiveness of firms and occasionally entire industries.

Porter's theory, along with the other modern, firm-based theories, offers an interesting interpretation of international trade trends. Nevertheless, they remain relatively new and minimally tested theories.