) The purpose of this proposal is to hold a consensus meeting on assessing clinical significance for quality of life (QOL) measurement in oncology. The major outcome of this consensus meeting will be to produce a monograph which sets out the primary methods, challenges, and solutions for assessing clinical significance for QOL measurement in oncology. We will bring together twenty of the leading experts on this topic to a """"""""think tank"""""""", with the goal of producing a state-of-the-science summary on this topic. We will identify six primary issues surrounding the assessment of clinical significance and assign teams of three to five of the experts to prepare draft summary documents in advance of the meeting. The meeting format will be targeted to promote the discussion of and refinement of the six draft documents by the twenty experts in QOL research. These documents subsequently will be gathered together into a single monograph to be published in the spring of 2001. In the fall of 2001, we will host a second meeting with open registration to discuss more fully and disseminate the material produced from the consensus meeting. Hence the ultimate product of this meeting will be to set out the state of the science in terms of assessing clinical significance for QOL measurement in oncology. This will provide tangible benefit to all oncology researchers who at present are struggling with the basic problem of how to measure QOL and to assess when a clinically significant change has occurred.