Systematic Reviews and Meta-Analyses

A systematic review is a rigorous, methodical synthesis of research evidence that answers a clearly defined question. Unlike traditional literature reviews, which may provide a broad overview or commentary on a topic, systematic reviews follow a structured process designed to minimize bias and maximize transparency and reproducibility. By comprehensively searching for, evaluating, and synthesizing all available studies on a given topic, systematic reviews provide policymakers, practitioners, and researchers with high-quality, actionable insights. 

Systematic reviews are increasingly valued across disciplines for their role in evidence-based practice and policy. They help clarify what is known, identify gaps in the literature, and inform decision-making by consolidating findings from multiple studies. 

Before embarking on a systematic review, it’s important to understand the different types of literature reviews and research syntheses

• Systematic Review: Uses explicit, pre-defined methods to identify, select, appraise, and synthesize research evidence relevant to a particular question. 

• Scoping Review: Maps the key concepts in a research area and the types of evidence available, without necessarily assessing the quality of that evidence or synthesizing findings in detail. 

• Rapid Review: Streamlines the systematic review process to produce evidence more quickly, often for policy or practice needs, with some concessions in methodological rigor. 

• Meta-Analysis: Quantitatively combines results from multiple studies using statistical methods (often conducted within a systematic review). 

• Narrative Review: Offers a descriptive summary of literature on a topic, typically without the systematic search and appraisal processes. 

• Umbrella Review: Synthesizes findings from multiple systematic reviews. 

• Other Research Syntheses: Sometimes reviews focus on specific methodologies (e.g., qualitative evidence synthesis or realist reviews). 

Systematic reviews (and other rigorous reviews) require significant resources—time, expertise, and access to research databases and full texts. Please consider the following before committing: 

• Is your research question clearly defined and answerable through existing studies? 

• Are you prepared to follow a rigorous, transparent process? Systematic reviews require protocol development, comprehensive searching, duplicate screening, and detailed data extraction. 

• Do you have the time and resources? Reviews can take at minimum weeks of committed time with a team (or using processes to speed up the review in earlier stages), but often months or longer, depending on scope and complexity. 

• Are you seeking to inform policy, guide practice, or identify research gaps? Systematic reviews are most valuable when the stakes are high and evidence synthesis must be thorough. 

If your needs do not align with the systematic review process, consider: 

• Scoping Reviews: For mapping broad areas or emerging topics. 

• Narrative Reviews: For providing context or introducing a subject. 

• Rapid Reviews: For urgent decision-making needs where time is constrained. 

• Evidence Maps: For visualizing the distribution of research on a topic.