In a meta-analysis, the I² statistic is reported as 82%. The forest plot shows wide confidence intervals for individual studies with several overlapping the null. The most appropriate next step is:
- A Proceed with a fixed-effects pooled estimate as the summary measure
- B Discard the meta-analysis as heterogeneity invalidates pooling
- C Use a random-effects model and explore sources of heterogeneity via subgroup analysis or meta-regression ✓
- D Apply the Mantel-Haenszel method assuming homogeneity
Correct answer: C. Use a random-effects model and explore sources of heterogeneity via subgroup analysis or meta-regression
Explanation
An I² of 82% indicates substantial heterogeneity (>75% by Higgins criteria), meaning study results differ more than expected by chance alone. A fixed-effects model is inappropriate here as it assumes a single true effect size. The correct approach is a random-effects model (which accounts for between-study variance, τ²) and investigation of heterogeneity sources through subgroup analysis, meta-regression, or sensitivity analysis. Heterogeneity alone does not mandate abandonment of the meta-analysis.
Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.
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