The commodity pattern of comparative advantage across countries is a central concept
in international trade theory. Since the concept is based upon autarkic prices which
are not observable in post-trade equilibria, its use in empirical research is most
difficult. The literature reports numerous alternative indices that purport to "measure"
comparative advantage. This paper examines the extent to which various measures are
consistent using a large sample of trade flows. The results have important implication
for judging empirical studies based upon particular choices of a measure for comparative