What best defines meta-analysis?

• A. Statistical analysis of results across multiple studies for integrating findings
• B. A single study analysis
• C. A qualitative narrative synthesis
• D. Data collection method

Answer: (A)

Meta-analysis is the statistical synthesis that combines results from multiple independent studies to produce a single, overall estimate of effect. This approach pools data to increase precision, improve power, and provide a more generalized conclusion than any one study could offer. It treats each study as contributing an effect size (such as a risk ratio or mean difference) and weights studies—often by inverse variance—to reflect their precision. It also allows assessment of consistency across studies and exploration of potential reasons for differences, using models like fixed-effects or random-effects and metrics like I-squared for heterogeneity. This makes meta-analysis a quantitative method for integrating findings across studies, which is fundamentally different from analyzing a single study, performing a qualitative narrative summary, or simply collecting data.