What is a Systematic Review Dr. Nancy Agens, Head, Technical Operations, Pubrica
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In Brief A systematic review is a secondary research as it requires a careful analysis of the quality, quantity, and consistency of research findings. Systematic reviews formulate research questions that are specifically targeted and designed to provide a complete summary of the issue based on evidence. The methodology used in systematic reviews is specific and precise, which intends to minimize bias by increasing the reliability of the drawn conclusion. I. INTRODUCTION A systematic review is a process of identifying comprehensive studies for a research specific question through evaluating the methods of the study, summarizing the results, presenting key findings, identifying reasons for produced results across the study and mentioning limitations with current knowledge. A systematic review is the most reliable source of evidence for clinical practices as it delivers thorough summary of primary research in response to the defined research question and it is also known as secondary research because of the nature and use of existing research study. Though systematic review can be performed on all primary research, they are often used for guideline development, and the findings are applied mainly within the healthcare systems. In a systematic review, the compiled information tends to be explicit and more transparent using reproducible methods. Further, it expresses a precise aim through rigorous search with predetermined eligibility criteria for studies, an assessment of the validity of
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the findings, a systematic presentation and synthesis of the included primary research studies. The methodology used in systematic reviews is specific and precise, which intends to minimize bias by increasing the reliability of the drawn conclusion. The produced results of a systematic review can be summarized either in text or graphic form, and it depends upon the nature of the primary data. As like primary research studies, there are reporting standards designed for systematic reviews as well. The PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses), provides a set of regulations on how to report a systematic review. Likewise, for selecting a secondary research question, there are designated formats. A systematic review question typically focused research question with narrow parameters and usually fitted into the PICO question format. One such example is "In people with multiple sclerosis, what is the extent to which a walking intervention, compared to no intervention, improves self-report fatigue?". Based on the specific guidelines, the primary two organization which administer the conducting of a systematic review are the Campbell Collaboration and the Cochrane Collaboration. While the Cochrane Collaboration focuses on the health sciences subject area, the Campbell collaboration works on other areas such as crime and justice, international development, education and social welfare. In addition to these organizations, the individual research team can work on systematic review in attempting to answer a research question.
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II. WHAT MAKES AN EXCELLENT SYSTEMATIC REVIEW? A good systematic review will include, A focused question Inclusion/exclusion criteria Search strategy Study selection Assess the quality of studies Synthesize study results Analysis and limitations A focused question - a systematic review is a research method used to address a specific research question and formulating a well-constructed research question is essential for a successful review. Inclusion/exclusion criteria – It studies the writers included or excluded and the reason. For instance, the most reliable method for conducting a review through randomized studies whereas for including or excluding studies, the author needs a logical reason. Search strategy – The reviewer must explain the methods used for finding relevant studies which include published and unpublished clinical trial reports, online database search, as well as approaching experts in finding unpublished data.
Study selection – Need to identify suitable study criteria and collect relevant data for conducting a systematic review. Assess the quality of studies – It helps in identifying the risk of bias in secondary research Synthesize study results - Upon similarity on the included data, the author must determine the effectiveness of an intervention using meta-analysis. Whereas the study is not much similar, the author can provide a narrative analysis by describing the initial results. Analysis and limitations – The review should discuss the addressed area of study, the findings, and how the review results change the existing limitations. Different types of reviews: There are many types of reviews addressing questions of effectiveness, questions about the prevalence of diagnostic accuracy, and prognosis. Different types of reviews include, Literature Review Meta-analysis Rapid review Scoping review Systematic review Systematized review Umbrella review
III. DIFFERENCES BETWEEN SYSTEMATIC AND LITERATURE REVIEWS Key section Question
Systematic review Mainly focused on question
Literature review one It describes an overview and not based on a single question review It has no protocol
Protocol Background Objectives Inclusion criteria
and
Search strategy
It follows peer protocol or plan Both the review presents the summaries of the available literature on a topic Study-specific objectives are No such objectives will be identified identified exclusion There are specific criteria to Not mandatorily specified be stated before the review is conducted A systematic search will be The search strategy will not
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conducted Process of selecting articles Clear and explicit Process of evaluating A comprehensive evaluation articles of the study as it mainly used in formulating guidelines Process of extracting Research question specific relevant information information extraction Results and data synthesis
Discussion
be mentioned Not described Evaluation of study quality may not be included
Extracting relevant information is not specific to a single question Clear summaries of studies Overview based on reviews will be provided based on where the quality of articles evidence may not be specified. An expert or group of professionals write them with a wellgrounded knowledge of the issues.
Reproduced from: Learning how to undertake a systematic review: part 1 DOI: 10.7748/ns2010.08.24.50.47.c7939
In summary, a systematic review is a search of all sources of evidence for relevant studies or on research question specific study. Predetermined reproducible criteria to screen for eligibility and relevance assessment of titles and the abstracts will be followed. Each study will then be assessed in terms of methodological quality, and finally, the evidence is synthesized. REFERENCE 1.
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Bettany-Saltikov, J & Fernandes, T 2010, 'Learning how to undertake a systematic review: Part 1', Nursing Standard (through 2013), vol. 24, no. 50, pp. 47-55 https://www.spi.ox.ac.uk/what-makes-a-goodsystematic-review The Systematic Review: An Overview American Journal of Nursing: March 2014 - Volume 114 Issue 3 p 53-58. DOI: 10.1097/01.NAJ.0000444496.24228.2c WilsonV. (2013). Research Methods: Systematic Reviews. Evidence-Based Library and Information Practice, 8(3), 83-84. https://doi.org/10.18438/B8CP5Z What is a systematic review? Jane Clarke Evid Based Nurs 2011 14: 64 http://dx.doi.org/10.1136/ebn.2011.0049 https://libraryguides.mcgill.ca/knowledgesyntheses/question
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