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 factor endowments 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. 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