Systematic reviews are a rigorous, comprehensive, and transparent review of the literature to answer a specific research question. Twelve months is a reasonable timeframe for completion. Some characteristics include:
a clearly stated set of objectives with pre-defined eligibility criteria for studies;
an explicit, reproducible methodology;
a systematic search that attempts to identify all studies that would meet the eligibility criteria;
an assessment of the validity of the findings of the included studies, for example through the assessment of risk of bias;
a systematic presentation, and synthesis, of the characteristics and findings of the included studies. (Green)
Systematic reviews began in the 1990’s, but have their roots in the use of meta-analysis and an evidence based approach to medical research in the 1970’s and 1980’s. Through the years, systematic reviews have expanded beyond medicine to other health sciences, social sciences, education, and other fields. (EPPI-Centre)
Standards and tools have been developed and refined to improve accuracy and efficiency.
Green S, Higgins JPT, Alderson P, Clarke M, Mulrow CD, Oxman AD. What is a systematic review? In: Higgins JPT, Green S (editors). Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0 [updated March 2011]. The Cochrane Collaboration, 2011EPPI-Centre. History of Systematic Reviews
Demeyin W. Traditional reviews vs. systematic reviews [Internet]. Students 4 Best Evidence. 2016 [cited 2018 Jan 16].
"Streamline traditional systematic review methods in order to synthesize evidence within a shortened timeframe" (Ganann)
Ganann R, Ciliska D, Thomas H. Expediting systematic reviews: methods and implications of rapid reviews. Implementation Science. 2010;5:56. doi.org/10.1186/1748-5908-5-56
Khangura S, Konnyu K, Cushman R, Grimshaw J, Moher D. Evidence summaries: the evolution of a rapid review approach. Systematic Reviews. 2012;1:10. doi:10.1186/2046-4053-1-10.
An exploratory approach to a research question; can serve as a preliminary approach to a systematic review to become familiar with the research literature by clarifying terminology and concepts of a topic
Munn Z, Peters MDJ, Stern C, Tufanaru C, McArthur A, Aromataris E. Systematic review or scoping review? Guidance for authors when choosing between a systematic or scoping review approach. BMC Med Res Methodol. 2018;18(1):143. Published 2018 Nov 19. doi:10.1186/s12874-018-0611-x
Chang, S. Scoping Reviews and Systematic Reviews: Is It an Either/Or Question? Ann Intern Med. 2018;169:502–503. doi: 10.7326/M18-2205
More about Scoping Reviews at AU.
"An umbrella review allows the findings of reviews relevant to a review question to be compared and contrasted. An umbrella review's most characteristic feature is that this type of evidence synthesis only considers for inclusion the highest level of evidence, namely other systematic reviews and meta-analyses."
Aromataris E, Fernandez R, Godfrey CM, Holly C, Khalil H, Tungpunkom P. Summarizing systematic reviews: methodological development, conduct and reporting of an umbrella review approach. International Journal of Evidence Based Healthcare. 2015 Sep;13(3):132–40. doi:10.1097/XEB.0000000000000055
Examples pulled from: Green S, Higgins JPT, Alderson P, Clarke M, Mulrow CD, Oxman AD. What is a systematic review? In: Higgins JPT, Green S (editors). Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0 [updated March 2011]. The Cochrane Collaboration, 2011EPPI-Centre. History of Systematic Reviews
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Critical review |
Aims to demonstrate writer has extensively researched literature and critically evaluated its quality. Goes beyond mere description to include degree of analysis and conceptual innovation. Typically results in hypothesis or model |
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Mapping review/ systematic map |
Map out and categorize existing literature from which to commission further reviews and/or primary research by identifying gaps in research literature |
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Meta-analysis |
Technique that statistically combines the results of quantitative studies to provide a more precise effect of the results |
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Mixed studies review/ mixed methods review |
Refers to any combination of methods where one significant component is a literature review (usually systematic). Within a review context it refers to a combination of review approaches for example combining quantitative with qualitative research or outcome with process studies |
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Overview |
Generic term: summary of the [medical] literature that attempts to survey the literature and describe its characteristics |
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Qualitative systematic review/ qualitative evidence synthesis |
Method for integrating or comparing the findings from qualitative studies. It looks for ‘themes’ or ‘constructs’ that lie in or across individual qualitative studies |
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State-of-the-art review |
Tend to address more current matters in contrast to other combined retrospective and current approaches. May offer new perspectives on issue or point out area for further research |
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Systematic search and review |
Combines strengths of critical review with a comprehensive search process. Typically addresses broad questions to produce ‘best evidence synthesis’ |
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Systematized review |
Attempt to include elements of systematic review process while stopping short of systematic review. Typically conducted as postgraduate student assignment |