Variables | Implication | Expected Symbol | Theoretical Assumptions |
GDPit | GDP of Japan’s source of import | + | It reflects soybean export supply ability of source of imports, the greater the amount of economic scale, the greater the potential ability to export, the greater the Japan’s soybean import |
GDPjt | Japan’s GDP | + | It reflects the Japan’s soybean import demand, the greater the amount of economic scale, the greater the potential ability to import, the greater the soybean import |
POPit | Population of Japan’s source of import | - | The more a country’s population, the larger the domestic market scale, the less need to rely on the international market, and smaller export scale, the smaller Japan’s soybean import |
POPjt | Population of Japan | + | It reflects the Japan’s soybean import demand, the more population, the greater the demand, the greater the import |
Dijt | The linear distance from Tokyo to capital or economic center of source of import | - | The farther the distance, the greater the cost of transportation, the smaller the import |
Pijt | The soybean import price from Japan’s source of import | - | It reflects the supply ability of soybean source of imports, import price rises, Japan will reduce soybean import from the country |
RATEijt | The exchange rate of source of imports currency against yen | + | It reflects the influence on Japan’s soybean import by bilateral exchange rate, the decrease of exchange rate means that Japan will pay a higher price, it will cause soybean import reduced |
PORit | Annual soybean production of source of import | + | It reflects the soybean supply ability of the source of imports, the higher the annual output, the stronger the soybean supply ability, the greater Japan’s import |
CONjt | Japan’s annual soybean consumption | + | It reflects the Japan’s soybean demand, the greater the annual consumption, the greater the demand for soybean import |
STOit | Soybean stocks of source of import | - | It reflects the soybean supply ability of source of imports, while domestic consumption remains the same, the more stocks shows the less potential exports, the less Japan’s import |
STOjt | Japan’s soybean stocks | - | It reflects the Japan’s soybean demand, when consumption remains the same, the more the stocks, the less soybean import need |
LANDjt | Japan’s soybean harvested area | - | It reflects the Japan’s soybean supply ability, the bigger the harvested area, the stronger the self-sufficiency, the less the import |
OILjt | Japan’s soybean oil import volume | - | It reflects the substitution effect of soybean oil import on soybean import, the more soybean oil import, the less soybean import |
T | Virtual variable of Japan’s implementation of the policy to labeling of GM food | - | After implementation to labeling of GM food, because the consumer awareness of GM, soybean import decreases |
F | Virtual variable of the 2008 financial crisis | - | After the outbreak of the financial crisis, the global economic recession began, Japan’s demand and source of imports supply capacity both decreased, soybean import decreased |