The Outcome Measures in Rheumatoid Arthritis Clinical Trials Conference has significantly contributed to the field of clinical outcome measurement. Agreement was achieved in designating a preliminary core set of 8 endpoints to be used as a minimum in every rheumatoid arthritis (RA) clinical trial of > or = 1 year: acute phase reactants, disability, pain, patient global assessment, physician global assessment, swollen joint count, tender joint count, and radiographic studies of joints. The discussions and nominal group exercises provided a mandate for full scale testing of approaches to compare the validity of different assessment techniques available for these 8 measures; to determine the minimum level of clinical importance for each of the measures; and to refine and validate the aggregation of outcome measures into indices, taking special care to ensure credibility in the eyes of clinicians, patients, and policy makers. The discussions made it clear that to select one intervention definitively over another, one must additionally consider outcomes such as drug toxicity, costs, and mortality. These aspects need to be explored systematically at subsequent conferences.