A researcher studying diet and colorectal cancer selects controls from the same hospital wards as cases. This may introduce which type of bias?

• A Neyman bias (prevalence-incidence bias)
• B Lead-time bias
• C Hawthorne effect
• D Berkson's bias ✓

Explanation

Berkson's bias (Berkson's fallacy) arises in hospital-based case-control studies when controls are chosen from the same hospital, leading to spurious associations because hospitalized controls differ systematically from the general population in their exposure profiles. Neyman bias occurs when cases are selected only from survivors of disease. Lead-time bias affects screening studies. Hawthorne effect is a performance bias from being observed.

Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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