Causation analysis involves determining what conditions are related to a compensable injury or illness; apportionment is the allocation of responsibility among two or more probable causes; and assessing impairment is based on the AMA Guides to the Evaluation of Permanent Impairment (AMA Guides). These three are separate activities, but sometimes all three must be addressed in a single evaluation and may be required for a specified jurisdiction (eg, California). Evaluators thus must ask if jurisdictional issues dictate or influence the approach to causation and apportionment; which edition of the AMA Guides to use; and how to approach causation and apportionment in the present case example: A 63-year-old woman with rheumatoid arthritis and systemic lupus erythematosus is assessed by an orthopedic surgeon who is the agreed medical evaluator (AME). In addition to her pre-existing rheumatoid arthritis and lupus, the individual also had Sjogren's syndrome, osteoarthritis, degenerative disc disease, left carpal tunnel syndrome, osteopenia, and obesity. She has undergone multiple surgical procedures, and treatment for her collagen vascular disease includes leflunomide (immunosuppressant), hydroxychloroquine, and prednisone. In this case, impairments were not the result of “cumulative trauma” but rather were secondary to underlying chronic inflammatory disease, and her occupational permanent impairment rating accordingly would be zero.