Which statement best describes the relationship between a systematic review and a meta-analysis?

Which statement best describes the relationship between a systematic review and a meta-analysis?

• A. Systematic review qualitatively synthesizes evidence
• B. Systematic review uses narrative descriptions only
• C. A meta-analysis quantitatively pools data across studies
• D. A systematic review is always devoid of data synthesis

Answer: (C)

Understanding the relationship between a systematic review and a meta-analysis starts with how evidence is brought together. A systematic review is a structured process that identifies, appraises, and summarizes all relevant studies on a question using explicit methods. A meta-analysis is a statistical technique used within that framework to combine the numerical results from multiple studies to produce a single, pooled estimate of effect. The key point is that meta-analysis is a quantitative form of data synthesis that can be part of a systematic review when the included studies are sufficiently similar and their data can be combined in a meaningful way. It increases precision and power by weighting studies according to size and variance and allows exploration of whether effects differ across studies. Some systematic reviews, however, do not perform meta-analysis—often because the studies are too heterogeneous in design, outcomes, or reporting, making a quantitative pooling inappropriate. In those cases, synthesis is narrative or descriptive rather than statistical. So the statement that meta-analysis quantitatively pools data across studies best captures the role of meta-analysis within the broader process of a systematic review.

Understanding the relationship between a systematic review and a meta-analysis starts with how evidence is brought together. A systematic review is a structured process that identifies, appraises, and summarizes all relevant studies on a question using explicit methods. A meta-analysis is a statistical technique used within that framework to combine the numerical results from multiple studies to produce a single, pooled estimate of effect.

The key point is that meta-analysis is a quantitative form of data synthesis that can be part of a systematic review when the included studies are sufficiently similar and their data can be combined in a meaningful way. It increases precision and power by weighting studies according to size and variance and allows exploration of whether effects differ across studies.

Some systematic reviews, however, do not perform meta-analysis—often because the studies are too heterogeneous in design, outcomes, or reporting, making a quantitative pooling inappropriate. In those cases, synthesis is narrative or descriptive rather than statistical.

So the statement that meta-analysis quantitatively pools data across studies best captures the role of meta-analysis within the broader process of a systematic review.