Figure 1From: The determination and measurement of functional disability in rheumatoid arthritisA partial causal model of disease activity and outcome in rheumatoid arthritis. Rectangles represent observed variables, and ovals and rounded rectangles represent latent (unobserved) variables. ESR/CRP, erythrocyte sedimentation rate/C-reactive protein; HAQ, Health Assessment Questionnaire; SF-36, Medical Outcomes Study Short Form 36; QOL, quality of life; JT, joint.Back to article page