Resume: Mortality from major bleeding in trauma patients is highest within the first six hours post-injury. Advances in patient management, driven by national guidelines and clinical trials, have significantly improved outcomes. However, variability in patient profiles, clinical presentations, and standard care practices complicates the assessment of treatment efficacy in clinical trials. In June 2024, international experts convened at the Critical Care Clinical Trialists (3CT) Workshop to examine the evolution of massive bleeding management and the impact of patient and treatment heterogeneity on trial design. This opinion article builds on the workshop discussions and underscores key considerations for the interpretation of large-scale studies. Three main conclusions emerged: First, the need for standardized definitions of "massive bleeding," "life-threatening bleeding," and "massive transfusion" to ensure consistent patient classification and treatment strategies. Second, the importance of tailored approaches that account for patient heterogeneity, including the careful selection of target populations and the use of appropriate primary endpoints. Third, the necessity of methodological adaptations in emergency research settings, such as implementing deferred consent procedures, conducting interim analyses, and using automated adjudication systems to improve objectivity and trial efficiency. In summary, harmonizing terminology, embracing clinical diversity, and refining trial design are essential to enhance the quality, comparability, and clinical relevance of research in massive bleeding. These measures ultimately aim to improve outcomes for critically bleeding patients.