The 'funnel plot' in systematic reviews is used to detect:
- A Confounding in individual studies
- B Between-study heterogeneity in effect estimates
- C Publication bias — asymmetry suggests missing small negative studies ✓
- D Selection bias in the primary study populations
Correct answer: C. Publication bias — asymmetry suggests missing small negative studies
Explanation
A funnel plot displays each included study's effect size against its precision (sample size or standard error). In the absence of publication bias, studies should distribute symmetrically in a funnel shape around the pooled estimate. Asymmetry — particularly absence of small studies with negative results — suggests publication bias, where only positive studies were published. Egger's test formally evaluates this asymmetry.
Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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