Quantification of the global severity of rheumatoid arthritis in a patient, based on a combination of several different specific measures, e.g. swollen 28-joint count, tender 28-joint count, erythrocyte sedimentation rate and patient global health assessment score. The trait is Experimental Factor Ontology identifier EFO_0009435 (arthritis disease activity score measurement). Also known as: DAS28, disease activity score.