Abstract
Two rheumatologists made judgments about 'current disease activity' in real patients and 'paper patients' with rheumatoid arthritis. Analysis of each set of judgments provides a model of judgment policy which contains only 3 clinical variables but explains over 94% of the variance in judgments. The judgment policy models differ markedly from each other and from the clinicians' own perceptions of their behaviour. Judgment policy modelling offers a means of improving co-ordination between clinical investigators within and between centres.