A meta-analysis of 12 trials shows a funnel plot that is markedly asymmetric, with small studies clustered on one side. The MOST likely explanation for this pattern is:
- A Heterogeneity of treatment effect across studies
- B Confounding by indication in the included trials
- C Publication bias favouring positive small studies ✓
- D Imprecision due to wide confidence intervals in large studies
Correct answer: C. Publication bias favouring positive small studies
Explanation
Funnel plot asymmetry — small studies concentrated on one side — classically indicates publication bias, because small studies with null or negative results are less likely to be published, leaving only positive small studies in the literature. The remaining options may contribute to heterogeneity or study quality concerns but do not produce characteristic funnel asymmetry. Trim-and-fill and Egger's regression are formal tests for this asymmetry.
Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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