Foreign outsourcing--the importing of some intermediate product (i.e., a portion of a final product or some good or service needed to produce a final product) that was once produced domestically--is not a new phenomenon, nor is it one that is economically distinct from other types of imports in terms of its basic economic consequences. A steadily rising level of trade in intermediate products is one of the salient characteristics of U.S. trade and world trade for the last 30 years. It has been estimated that as much as a third of the growth of world trade since 1970 has been the result of such outsourcing worldwide. While foreign outsourcing may seem different from traditional notions of trade in that it involves exchange of a productive resource (capital or labor) rather than an exchange of a final good and service, the ultimate economic outcome is exactly the same: a net increase in economic efficiency through the elimination of economic inefficiencies that occur when countries use only the productive resources found within their borders. This gain is not likely to be achieved, however, without causing costly disruptions for the particular workers and sectors tied to the now-imported good.