[Consensus doesn't always mean agreement: limitations of consensus methods in health services].

Taking decisions in uncertain situations has led to a high use of the consensus methods (Nominal Group Technique, Delphi Method, and Consensus Conferences) in the health services. The review made in this article shows that the appropriate use of these techniques requires a high degree of methodologic precision, especially in relation to the financer's declaration of objectives, the appropriate selection of the participants, previous realization of a synthesis of the preexistent information, the definition of the agreement degree which leads to the consensus and in the evaluation of its impact.