The formula to calculate the Balassa Index (BI) is:
\[ \text{BI} = \left(\frac{\text{Eij}}{\text{Ej}}\right) / \left(\frac{\text{Wi}}{\text{W}}\right) \]
Where:
Let's say the export of a specific product from a specific country (Eij) is 1000 units, the total export of the specific country (Ej) is 50000 units, the world export of the specific product (Wi) is 200000 units, and the total world export (W) is 10000000 units. Using the formula:
\[ \text{BI} = \left(\frac{1000}{50000}\right) / \left(\frac{200000}{10000000}\right) = 1 \]
So, the Balassa Index is 1, indicating no comparative advantage or disadvantage.