Globalization triggers the mutual expression, and sometimes the clash, of people's worldviews. Such views, either a consumer's individual preferences or those shared within a community (i.e. collective preferences), typically generate trade-related measures that aim at regulating the relationship between trading partners accordingly. Clashing collective preferences may lead to harsh disputes before the World Trade Organization (WTO), which typically require its adjudicatory bodies to walk the thin line deciding between Members protecting legitimate consumer concerns and Members protecting domestic industries. The quality of these WTO decisions is hence of utmost importance, and the assessment of consumers' preferences is a crucial element that often sparks debate. Erroneous assessments have been submitted to WTO adjudicators in past cases. Using such assessments of collective preferences in WTO adjudication puts the legitimacy of the organization at risk. The present work therefore sheds light on the methods of assessing consumer preferences in WTO adjudication. It provides important analysis on the concept and role of consumers' preferences in the context of WTO law and litigation, and investigates how the WTO adjudicatory bodies have so far dealt with the challenges relating to their assessment. Its recommendations to improve the assessment of collective preferences in WTO adjudication serves to enable WTO Members and adjudicators to identify genuine preferences and to measure their importance against competing preferences. As the issue of clashing collective preferences may go beyond the scope of WTO adjudication, this work also provides advice to other stakeholders.