The article discusses the use of consensus methods, particularly the Delphi process and the nominal group technique, in health research. These methods are used to address situations where there is insufficient or contradictory information, and they allow for a broader range of study types and qualitative assessments of evidence. The Delphi process involves multiple rounds of questionnaires to gather and refine opinions, while the nominal group technique uses structured meetings to gather and discuss information from experts. Both methods aim to determine the extent of agreement and resolve disagreements. The article outlines the steps involved in each method, the key methodological issues, and their applications in various fields such as technology assessment, education, and clinical practice. It emphasizes the importance of sound methodology, appropriate presentation of findings, and the relevance and systematic use of results. The article concludes by highlighting the role of consensus methods in identifying and measuring uncertainty in health research and their use in forming guidelines and policies.The article discusses the use of consensus methods, particularly the Delphi process and the nominal group technique, in health research. These methods are used to address situations where there is insufficient or contradictory information, and they allow for a broader range of study types and qualitative assessments of evidence. The Delphi process involves multiple rounds of questionnaires to gather and refine opinions, while the nominal group technique uses structured meetings to gather and discuss information from experts. Both methods aim to determine the extent of agreement and resolve disagreements. The article outlines the steps involved in each method, the key methodological issues, and their applications in various fields such as technology assessment, education, and clinical practice. It emphasizes the importance of sound methodology, appropriate presentation of findings, and the relevance and systematic use of results. The article concludes by highlighting the role of consensus methods in identifying and measuring uncertainty in health research and their use in forming guidelines and policies.