Export Specialization Index

The export specialization (ES) index is a slightly modified RCA index, in which the denominator is usually measured by specific markets or partners. It provides product information on revealed specialization in the export sector of a country and is calculated as the ratio of the share of a product in a country’s total exports to the share of this product in imports to specific markets or partners rather than its share in world exports:

ES = (xij/Xit) / (mkj/Mkt)

Where xij and Xit are export values of country i in product j, respectively, and where mkj and Mkt are the import values of product j in market k and total imports in market k. The ES is similar to the RCA in that the value of the index less than unity indicates a comparative disadvantage and a value above unity represents specialization in this market.