A researcher reports that countries with higher chocolate consumption have more Nobel laureates per capita and concludes that eating chocolate increases individual intelligence. This erroneous conclusion is an example of:
- A Berkson's bias
- B Ecological fallacy ✓
- C Recall bias
- D Effect modification
Correct answer: B. Ecological fallacy
Explanation
An ecological fallacy occurs when associations observed at the group level are wrongly applied to individuals. Group-level correlations can be distorted by confounders such as national wealth, which here explains both variables. Berkson's bias is selection bias in hospital-based studies, recall bias is differential exposure ascertainment, and effect modification is a true biologic interaction, not a grouping error.
Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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