Setting the scene and posing the questions.

Rheumatoid arthritis (RA) is a common disabling disease. We are only just developing the necessary skills to assess the outcome of RA in both the short and long term. We can measure outcome in terms of radiological change, functional capacity and death. Patterns of disease onset and process measures, such as ESR and CRP, help to predict outcome. Without satisfactory methods of documenting the natural history of RA we cannot hope to be able to identify effective therapies or to develop sensible policies for their use.