The RCA is a metric that compares a country’s share of exports in a particular segment to the global share of those exports. Therefore, the metric is helpful for assessing and understanding a country’s competitive position in each segment within the global market. The expression of the RCA is as follows:
Where represents the exports of country in segment , represents the total exports of country .1 is the world’s exports of segment , while accounts for the world’s total exports of all segments. Therefore, a value of the RCA above 1 indicates a comparative advantage.
The Herfindahl-Hirschman Index (HHI), which is calculated as the sum of the squared market shares of each country for a certain good, is used to measure the level of concentration in each market. A three-year average of trade flows is used throughout the analysis to mitigate the impact of noise and outliers. The index would equal 1 in the case of a monopoly and converge to 0 with a large number of atomistic suppliers. Thus, the closer to zero, the lower the concentration.
The interpretation of the HHI index level varies depending on the context.2 Vicard and Wibaux (2023[1]) and Bonnet and Ciani (2023[2]) deem a product to be concentrated when the index is above 0.4. Following Kowalski and Legendre (2023[3]), this paper considers that markets with an HHI between 0.15 and 0.25 are moderately concentrated, while markets with an HHI greater than 0.25 are highly concentrated.
Notes: 1. The set {P} contains all of the goods available in the UN Comtrade database.
1. This report establishes three criteria to assess Costa Rica’s dependence on its imports. First, gross imports of good by Costa Rica must be highly concentrated overall (HHI >0.4). Additionally, the ratio of exports to imports of the good in Costa Rica must be lower than the 90th percentile of the distribution and the imports from Costa Rica of good need to amount to USD 1 million or more. In the absence of production data, these criteria help identify trade dependencies while avoiding misclassification of countries with significant domestic production of good .