Objective: To identify, in people known to have gout, the testable, key components of a standard definition of gout flare for use in clinical research. Methods. Consensus methodology was used to identify key elements of a gout flare. Two Delphi exercises were conducted among different groups of rheumatologists. A cognitive mapping technique among 9 gout experts with hierarchical cluster analysis provided a framework to guide the panel discussion, which identified the final set of items that should be tested empirically. Results. From the Delphi exercises, 21 items were presented to the expert panel. Cluster analysis and multidimensional scaling showed that these items clustered into 5 concepts (joint inflammation, severity of symptoms, stereotypical nature, pain, and gout archetype) distributed along 2 dimensions (objective to subjective features and general features to specific features of gout). Using this analysis, expert panel discussion generated a short list of potential features: joint swelling, joint tenderness, joint warmth, severity of pain, patient global assessment, time to maximum pain, time to complete resolution of pain, an acute-phase marker, and functional impact of the episode. Conclusion. A short list of features has been identified and now requires validation against a patient- and physiciandefined gout flare in order to determine the best combination of features. © 2009, American College of Rheumatology.