To justify certain sanitary and phytosanitary measures vis-à-vis New Zealand apple fruit, Australian authorities performed an import risk assessment that was riddled with scientific uncertainty. The quality and reliability of this assessment was the central bone of contention between the parties in the Australia–Apples dispute. In consequence, it featured prominently in the Appellate Body's discussion. In commenting on the Appellate Body Report, we are concerned with the standard of review of Members' decisions that are taken in situations of factual uncertainty. We discuss the elements in a Member's risk assessment that, in our view, should be considered ‘off limits’ for review by Panels if such assessment was performed in the presence of uncertain scientific facts, and how high degrees of uncertainty affect a Panel's ability to assess alleged less-trade-restrictive alternatives. Relying on findings from the disciplines of economics, decision analysis, and risk management, we introduce a basic framework for decisionmaking in conditions of uncertainty. We submit that certain types of decisions taken by the risk assessor cannot be subject to external review, since they necessarily contain subjective trade-offs on the part of the risk assessor. Applying our theoretical insights to the Apples case, we offer a series of recommendations concerning Panels' discretion to review Members' risk assessments and suggest concrete modifications to the standard of review currently applied by the Appellate Body.