In a meta-analysis, the reviewer plots the study effect estimates against their standard errors. The resulting plot is markedly asymmetrical, with a visible gap where small negative studies should appear. This finding most strongly suggests:

• A Effect modification
• B Publication bias ✓
• C Random sampling error
• D Overmatching

Explanation

B funnel plot should be symmetrical around the pooled estimate if all trials have been published. Asymmetry, typically a gap among small studies with null results, indicates that small negative trials were not published, which is publication bias. Formal tests such as Egger's regression or Begg's rank correlation quantify this asymmetry. Effect modification produces differing effects across subgroups, not a missing quadrant of the plot, and random error scatters points symmetrically.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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