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Systematic Reviews and Meta Analyses

Systematic Reviews and Meta Analyses

When searching for evidence-based information, one should select the highest level of evidence possibleSystematic Reviews and Meta Analyses are considered to be the gold standard for healthcare decision-making as they are known to include the best available evidence to answer health research questions. Systematic reviews and meta-analyses have been critically appraised and are considered to be "filtered" information. The quality of a study has already been evaluated and recommendations have been made for its application in practice. Information that has not been critically appraised is considered "unfiltered," and would include original research studies that have not yet been synthesized or aggregated. When searching for evidence-based practice articles in the AU Libraries' databases, you will be able to select articles that focus on the specific type of EBP study design (such as a systematic review) that you need for your research.

Systematic reviews focus on a specific clinical question. A systematic review attempts to collate empirical evidence that fits predetermined eligibility criteria to answer a specific research question. An extensive literature search is conducted to identify all studies utilizing sound methodology on the topic of interest. The studies are reviewed and the results are summarized according to the predetermined criteria. Systematic reviews are more exhaustive than literature reviews as they may include both published and unpublished literature (also known as "grey literature"). Grey literature is often more current than published literature and may have less publication bias. Grey literature includes unpublished studies, reports, dissertations, conference papers and abstracts, governmental research, and ongoing clinical trials.

A short video explaining systematic reviews from The Cochrane Library:


Meta-Analysis is a specialized subset of systematic reviews. A systematic review collects all possible studies related to a given topic and reviews and analyzes their results. Meta-analysis is the use of statistical techniques in a systematic review to integrate the results of the included studies to conduct statistical inference. Not all systematic reviews include meta-analysis, but all meta-analyses are found in systematic reviews. A meta-analysis is a valid, objective, and scientific method of analyzing and combining different results.