The normalized revealed comparative advantage index

and time. Therefore， the NRCA index is comparable across commodity， the NRCA index provides a useful tool for quantitative regional research， In this paper， especially for studies on regional comparative advantage. ， we propose the normalized revealed comparative advantage (NRCA) index as an alternative measure of comparative advantage. The NRCA index is demonstrated capable of revealing the extent of comparative advantage that a country has in a commodity more precisely and consistently than other alternative RCA indices in the literature. As a result， country，。