Healthy user bias
Encyclopedia
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 to on average 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/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 (ie. someone in ill-health is unlikely to have a job as manual laborer).
healthy worker effect
C.-Y. Li and F.-C. Sung. A review of the healthy worker effect in occupational epidemiology. Occupational Medicine 1999;49:225-229
Bias
Bias is an inclination to present or hold a partial perspective at the expense of alternatives. Bias can come in many forms.-In judgement and decision making:...
that can damage the validity of epidemiologic studies testing the efficacy
Efficacy
Efficacy is the capacity to produce an effect. It has different specific meanings in different fields. In medicine, it is the ability of an intervention or drug to reproduce a desired effect in expert hands and under ideal circumstances.- Healthcare :...
of particular therapies or interventions. Specifically, it is a sampling bias: the kind of subjects that voluntarily enroll in a clinical trial
Clinical trial
Clinical trials are a set of procedures in medical research and drug development that are conducted to allow safety and efficacy data to be collected for health interventions...
and actually follow the experimental regimen are not representative of the general population. They can be expected to on average 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/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 (ie. someone in ill-health is unlikely to have a job as manual laborer).
healthy worker effect
C.-Y. Li and F.-C. Sung. A review of the healthy worker effect in occupational epidemiology. Occupational Medicine 1999;49:225-229