The healthy worker effect. Selection of workers and work forces.

The favorable health status of employed populations in comparison to that of the general population is often called the "healthy worker effect," and most researchers feel that it results from the selection of healthy individuals during the hiring process. However, other mechanisms may also contribute to the healthy worker effect. In particular, the healthy worker effect may reflect the selection, for epidemiologic study, of relatively advantaged workforces in terms of socioeconomic status and health. Evidence of differential health by socioeconomic status within the workforce is reviewed, and its possible role in the healthy worker effect is discussed.