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Systematic Reviews

What is a Systematic Review?

Systematic reviews seek to collate evidence that fits pre-specified eligibility criteria in order to answer a specific research question. They aim to minimize bias by using explicit, systematic methods documented in advance with a protocol.

Stages of a Systematic Review
Stage What is involved
Planning Assemble a team
Develop an answerable research question
Register a Protocol
Search for similar systematic reviews
Begin developing your inclusion and exclusion criteria
Searching Identify sources to search
Develop a list of search terms
Build your search strings
Document your process
Collect and organize your results
Analysis

Finalize your inclusion and exclusion criteria
Screen the results
Appraise the literature
Extract the data

Summarize

Synthesis your results
Summarize your main findings
Write a finalized report on the review
Optional: Publish results in an academic journal

All guidelines governing the creation of systematic reviews recommend the involvement of a librarian or information professional on your systematic review team.  We recommend you work with a librarian during the planning and searching phase of your systematic review. 

The National Academics of Sciences, Engineering, and Medicine developed Standards for Systematic Reviews.  Two standards include involving a librarian.

Standard 3.1.1: Work with a librarian or other information specialist training in performing systematic reviews to plan the search strategy.
Standard 3.1.3: Use an independent librarian or other information specialist to peer review the search strategy

Higgins JPT, Thomas J, Chandler J, Cumpston M, Li T, Page MJ, Welch VA (editors). Cochrane Handbook for Systematic Reviews of Interventions version 6.1 (updated September 2020). Cochrane, 2020. Available from www.training.cochrane.org/handbook.

Common Misconceptions & Other Review Types

The term "Systematic Review" is frequently used, without the full understanding of the process.  Depending on your information needs and research question, there may be a better review type for you to use.
 

How a systematic review differs from a literature review
  Systematic Review Literature Review
Question Focused on a single question Not necessarily focused on a single question, but may describe an overview
Protocol A peer review protocol or plan in included No protocol is included
Background Both provide summaries of the available literature on a topic
Objective Clear objectives are identified Objectives may or may not be identified
Inclusion/Exclusion Criteria Criteria is stated before the review is conducted Criteria not specified
Search strategy Comprehensive search conducted in a systematic way Strategy not explicitly stated
Selecting articles Usually clear and explicit Not described in a literature review
Evaluating articles Comprehensive evaluation of study quality Evaluation of study quality may or may not be included
Extraction of data Usually clear and specific The process is not explicit and clear
Results & data synthesis Clear summaries of studies based on high quality evidence Summary based on studies where the quality of articles may not be specified.  May be influenced by the reviewer's theories, needs, and beliefs.
Discussion Written by an expert or group of experts with a detailed and well grounded knowledge of the issues

Adapted from Bettany-Saltikov, J. (2010). Learning how to undertake a systematic review: part 1. Nursing Standard (Royal College of Nursing (Great Britain) : 1987), 24(50), 47–55.

Other misconceptions surrounding a systematic review:

  • Systematic reviews are the same as ordinary reviews, only bigger
  • Systematic reviews include only randomized controlled trials
  • Systematic reviews require the adoption of a biomedical model of health
  • Systematic reviews are of no relevance to the real world
  • Systematic reviews necessarily involve statistical synthesis
  • Systematic reviews have to be by experts
  • Systematic reviews can be done without experience information/library support
  • Systematic reviews are a substitute for doing good quality individual studies

Petticrew, M. (2001). Systematic reviews from astronomy to zoology: myths and misconceptions. BMJ: British Medical Journal (International Edition), 322(7278), 98. https://doi.org/10.1136/bmj.322.7278.98

Other Review Types

Review Type Characteristics The Search Accomplishes
Literature Review/Narrative Review Involves a process of identifying sources to include for review
Synthesizes the information
Analyzes the results for their contribution to the literature body
 
May or may not include comprehensive searching

Identifies what has been accomplished in the literature
Identifies gaps of knowledge
Builds on previous work
May be biased to support author's view by omitting articles that do not support research question

Mapping Review Map out and categorize existing literature Completeness of searching determined by time/scope constraints Identifies gaps of knowledge
Useful to support additional reviews or new research
Overview Summary of the literature May or may not include comprehensive searching Surveys the literature and describes it's characteristics
Provides a broad summation of a topic
Scoping Review Preliminary assessment of the potential size and scope of available research literature
May include research in progress
Completeness of searching determined by time/scope constraints.

Identifies the nature and extent of research evidence
Can support the need of a full systematic review

Umbrella Review Specifically refers to compiling evidence from multiple reviews into one accessible and usable document Identification of component reviews, but no search for primary studies Highlights other reviews
Provides a quick overview on a topic
Requires the pre-existence
of the narrower component reviews

For more information on other review types, visit the Literature Review Guide.

Grant, M. J. and Booth, A. (2009), A typology of reviews: an analysis of 14 review types and associated methodologies. Health Information & Libraries Journal, 26: 91–108. doi:10.1111/j.1471-1842.2009.00848.x

Librarian Support

Whether you wish to move forward with an actual systematic review or another type, the A.T. Still Memorial Librarians are happy to assist you throughout the process.  Specific help is outlined on each part of the process, below is a general overview of how we can assist.

  • Planning phase
    • Determine if your research question is appropriate for a systematic review or another review type
    • Educate you and your team on the systematic review process, the main concepts, and important definitions you should know
    • Determine the role of the librarian, either as a team member or in an advisory role
    • Provide useful resources for various phases of the systematic review
    • Locate other systematic reviews relevant to your topic
  • Search Phase
    • Recommend databases for searching
    • Identify keywords and controlled vocabulary for searching
    • Assist in building the search string for quality results
    • Identify what limits to apply to your results
    • As a team member, the librarian can conduct the literature search for the content experts to review.
  • Organizing Results
    • Educate the team on citation management options
    • Demonstrate how to utilize EndNote
    • As a team member, the librarian can gather all relevant results and organize them for the content experts.
  • Analysis Phase
    • Educate team members on creating inclusion and exclusion criteria
    • Educate team members on screening articles and appraising the literature
    • As a team member, the librarian can serve as a tie breaker for article inclusion disagreements
  • Summarize Phase
    • Provide resources on summarizing the review and reporting standards
    • Provide a list of journals for publication
    • As a team member, the librarian can author or contribute to the final report on aspects of the systematic review