In a meta-analysis of trials testing a new antihypertensive, a funnel plot shows asymmetry with a conspicuous absence of small negative studies in the lower-left region. The MOST likely explanation is:
- A Publication bias favouring positive small studies ✓
- B True heterogeneity of treatment effect across populations
- C Language bias excluding foreign-language negative trials
- D Attrition bias in individual trials
Correct answer: A. Publication bias favouring positive small studies
Explanation
Funnel plot asymmetry with missing small negative studies in the lower-left corner is the classic signature of publication bias — small studies with negative results tend not to be published, leaving only positive small studies visible. True heterogeneity would produce scatter across all quadrants rather than systematic absence in one region. Language bias contributes but produces a less distinctive pattern. Attrition bias affects internal validity of individual trials, not the meta-analytic funnel.
Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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