A cohort study compares mortality among employees of a large chemical plant with the general population of the region and finds that factory workers have significantly lower all-cause mortality than the general population. What is the most likely explanation?
- A Hawthorne effect
- B Neyman's bias
- C Healthy worker effect ✓
- D Ecological fallacy
Correct answer: C. Healthy worker effect
Explanation
The healthy worker effect is a selection bias seen when an occupational cohort is compared with the general population. Employed individuals must be reasonably fit to obtain and retain work, so workers have lower baseline mortality and morbidity than the general population, which includes the chronically ill and disabled. This can mask genuine occupational hazards and may even make a harmful workplace appear protective against overall mortality.
Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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