Statistical study of variation in systemic and articular indexes

Serial appraisals of rheumatoid activity by the systemic and articular indexes, performed by seasoned observers on patients who were accustomed to this type of examination, show an interobserver variation no greater than inter‐laboratory variations in determinations made on stock samples for uric acid, albumin and hemoglobin. However, the variation found when medical students examined new patients was considerably higher. Interobserver variation was not significantly greater than intraobserver variation. The precision and sensitivity of the various items composing the indexes are compared.