What is a Systematic Review / Meta- Analysis?
A systematic review or meta-analysis is a study of studies. These reviews aim to collect all existing evidence to address a specific research question. The final product can then be used to inform clinical decision-making, policy, and research. Systematic reviews and meta-analyses are conducted by a research team, rather than an individual researcher, to take advantage of specialized knowledge and expertise, facilitate expedited review of studies, and reduce bias.
It is important to note that all meta-analyses are systematic reviews, but not all systematic reviews are meta-analyses.
| |
Systematic review |
Meta-analysis |
| METHOD |
Systematically search for, appraise, and synthesize research evidence |
Statistically combine the results of quantitative studies to provide a more precise effect of the results |
| FORMAT |
Results are typically narrative, may have tabular component |
Results are graphical and tabular with narrative commentary |
| CONTENT |
Analyzes what is known; recommendations for practice. Identifies what remains unknown; uncertainty around findings, recommendations for future research |
Numerical analysis of measure of effect assuming absence of heterogeneity. |
There are six steps to a systematic review/meta-analysis:
- Plan – Frame research question, determine inclusion and exclusion criteria for studies, create project management outline including deadlines and responsibilities, and develop protocol.
- Identify – Determine search terms and databases to search, retrieve studies and document findings.
- Evaluate – Screen, select, sort, and appraise studies.
- Collect & Code – Determine forms, code selected studies, and synthesize data extracted.
- Explain – Analyze findings and put them into context.
- Summarize – Write up the report.
These steps usually take a minimum of 6 months to complete, and can take as long as a year or more. The literature search is a critical part of conducting systematic reviews and errors made in the search process can result in biased or incomplete evidence. Researchers should having a general sense of the literature in the field before embarkig on a systematic review, including knowledge of key works that have been published and specialized terminology. The criteria used to include/exclude evidence is pre-defined and is linked to the research question. Explicit methods to minimize bias and increase transparency are used to produce reliable synthesis of information.
