| Differences in factor endowments | NONE YET |
| Variety and quality of goods | NONE YET |
| Gains from specialization | http://opengecko.com/economics/reasons-for-trade/ – Milton Friedman’s Pencil |
| Political | NONE YET |
| Absolute and comparative advantage (numerical and diagrammatic representations) Higher level extension topic | http://opengecko.com/ib-economics/economics-game-ricardo-coconuts-and-a-desert-island/
http://opengecko.com/economics/understanding-comparative-advantage/ |
| Comparative Advantage and opportunity cost Higher level extension topic | http://opengecko.com/economics/reasons-for-trade/
http://opengecko.com/economics/understanding-comparative-advantage/ |
| Limitations of the theory of comparative advantage Higher level extension topic | NONE YET |
