Three methodological problems are commonly faced by researchers investigating relationships between severity and duration of illness among patients with rheumatoid arthritis (RA). (1) Linear regression techniques yield biased estimates when measures of severity are continous but range between...

Data from the National Health and Nutrition Examination Survey I, 1971-1975 (NHANES I) were used to analyze associations among highest education level and arthritis. The dependent variables indicated whether the respondent had ever been diagnosed with any form of arthritis by a physician (10,678...