Healthy user bias  From Wikipedia, the free encyclopedia Jump
to: navigation, search  The healthy user bias is a bias that can
damage the validity of epidemiologic studies testing the
efficacy of particular therapies or interventions. Specifically,
it is a sampling bias: the kind of subjects that voluntarily
enroll in a clinical trial and actually follow the experimental
regimen are not representative of the general population. They
can be expected, on average, to be healthier as they are
concerned for their health and are predisposed to follow medical
advice, both factors that would aid one's health. In a sense,
being healthy or active about one's health is a precondition for
becoming a subject of the study, an effect that can appear under
other conditions such as studying particular groups of workers
(i.e. someone in ill health is unlikely to have a job as manual
laborer).  Further reading[edit]    • Li, C. -Y.; Sung, F. -C.
(1999). "A review of the healthy worker effect in occupational
epidemiology". Occup