This book addresses injury and causation issues in the context of antidumping, countervailing duty (CVD) and safeguard investigations that are regulated under the WTO. It has long been argued that trade remedy instruments should be used only if there is a strong link between imports and the injury alleged by the domestic industry in the importing country. The book traces the origin and negotiating history of trade remedy agreements and demonstrates that terms such as “principal cause,” “substantial cause” and “a cause in and of itself” are not warranted in such instruments. In light of the experiences of key users of trade remedy instruments and the WTO Doha Round Rules negotiations, the book argues that causation determination does not require mathematical precision. Econometric or quantitative tools may be suggested, but such tools need not undermine the policy-laden nature of trade remedy instruments. Accordingly, it suggests the use of weak-necessity and strong sufficiency tests such as the Necessary Element of a Sufficient Set (NESS) test with regard to injury and causation.