Skip to Main Content
Nova southeastern University logo Martin and Gail Press Health Professions Division Library Logo

Medical Sciences: Systematic Review Overview

Recommended resources for the College of Osteopathic Medicine

Getting Started

A systematic review attempts to collate all empirical evidence that fits pre-specified eligibility criteria in order to answer a specific research question. The key characteristics of a systematic review are: a clearly defined question with inclusion & exclusion criteria; rigorous & systematic search of the literature; critical appraisal of included studies; data extraction and management; analysis & interpretation of results; and report for publication. Systematic reviews should be carried out according to a predefined protocol that sets out the scope of the systematic review and details of the methodology to be used throughout the review. 

Components of a Systematic Review

Key components of a systematic review include:

  • Systematic and extensive searches to identify all the relevant published and unpublished literature.
  • Study selection according to predefined eligibility criteria
  • Assessment of the risk of bias for included studies
  • Presentation of the findings in an independent and impartial manner
  • Discussion of the limitations of the evidence and of the review.

Systematic reviews can evaluate a range of evidence; qualitative, quantitative or both. Appropriate methods of synthesis should be used for different types of evidence.

The systematic review process has been developed to minimize bias and ensure transparency. Methods should be adequately documented so that they can be replicated.

When conducted well, systematic reviews should give us the best possible estimate of any true effect. An assessment of the methodological quality of reviews should highlight the limitations of a review.

Understanding Research Evidence

Understanding and interpreting research evidence is an important part of practicing evidence-informed public health. This short video from the National Collaborating Centre for Methods and Tools explains the types of reviews and what kind are needed.

Online Tutorials

What does it take to do a systematic review?

Time: On average, systematic reviews require 18 months of preparation.

…to find out about a healthcare intervention it is worth searching research literature thoroughly to see if the answer is already known. This may require considerable work over many months…” (Cochrane Collaboration)

 The suggested timeline for a Cochrane review is: 

  • Preparation of protocol 1 – 2 months
  • Searches for published and unpublished studies 3-8 months
  • Pilot test of eligibility criteria 2-3 months
  • Inclusion assessments 3-8 months
  • Pilot test of ‘Risk of bias’ assessment 3 months
  • Validity assessments 3-10 months
  • Pilot test of data collection 3 months
  • Data collection 3-10 months
  • Data entry 3-10 months
  • Follow up of missing information 5-11 months
  • Analysis 8-10 months
  • Preparation of review report 1-11 months
  • Keeping the review up-to-date 12 months

A team: A systematic review can't be done alone! You need to work with subject experts to clarify issues related to the topic; librarians to develop comprehensive search strategies and identify appropriate databases; reviewers to screen abstracts and read the full text; a statistician who can assist with data analysis; and a project leader to coordinate and write the final report.

A clearly defined question: Clarify the key question(s) of you systematic review and the rationale for each question. Use the PICO framework to identify key concepts of the question. Determine inclusion/exclusion criteria.  Build a good clinical question to facilitate searching for a precise answer.

Structure of a clinical question:

  • Patient population or problem - What are the significant characteristics of the patient or the population?
  • Intervention - What is the main intervention or treatment?
  • Comparison - Are you considering another intervention as a comparison to the first?
  • Outcome - What is the effect of the treatment/intervention? (Outcome factor) How will you measure it?

A written protocol: You need to write a protocol outlining the study methodology. The protocol should include the rationale for the systematic review, key questions broken into PICO components, inclusion/exclusion criteria, literature searches for published/unpublished literature, data abstraction/data management, assessment of methodological quality of individual studies, data synthesis, and grading the evidence for each key question.

Official Protocol Resources:

A registered protocolAfter you write the protocol, you should register it with PROSPERO, an International Prospective Register of Systematic Reviews. Registration is free and open to anyone undertaking systematic reviews of the effects of interventions and strategies to prevent, diagnose, treat, and monitor health conditions, for which there is a health related outcome.

Comprehensive literature searches: First, identify systematic reviews that may address your key questions. Then, identify appropriate databases and conduct comprehensive and detailed literature searches that can be documented and duplicated. Your research strategy has to be reproducible. 

Citation management: You should have working knowledge of EndNote to help manage citations retrieved from literature searches.

Follow reporting guidelines: Use appropriate guidelines for reporting your review for publication.

For detailed literature information about the process: See Handbooks for Doing Systematic Reviews

Steps of a Systematic Review

These are the steps of a Systematic Review adapted from Cochrane Canada 2011, Session three: A 'snapshot' of the steps of conducting a Cochrane Review (part 1).:

Steps of a review (PIECES)

  • PPlanning-  the methods of the systematic review are generally decided before conducting it.  
  • IIdentifying- searching for studies which match the preset criteria in a systematic manner.
  • EEvaluating- sort all retrieved articles (included or  excluded) and assess the risk of bias for each included study.
  • CCollecting/combining: each study is coded with preset form, either qualitatively or quantitatively synthesize data.
  • EExplaining:  placed results of synthesis into context, strengths and weaknesses of the studies. 
  • SSummarizing: report is provides description of methods and results in a clear and transparent manner.                                       


Methods and Further Reading

How can the Library help?

Library Liaisons can partner with you and advise on how to start a systematic review. 

Basic Service includes

  • Provide overview of the systematic review (SR) process
  • Inform researcher of SR standards (IOM, PRISMA, Cochrane)
  • Assist researcher with formulating the research question
  • Suggest databases for searching
  • 1 meeting required

Students needing help with systematic reviews can contact liaison librarians to learn about the process.                               

Systematic review service will be  available to faculty, residents, fellows, and post-docs. 

Full Services includes

  • Provide overview of the systematic review (SR) process
  • Inform researcher of SR standards (IOM, PRISMA, Cochrane)
  • Assist researcher with formulating the research question
  • Suggest databases for searching
  • Design the main search strategy
  • Translate the search across multiple databases
  • Conduct the search in multiple databases
  • De-duplicate and merge the citations
  • Deliver citations in preferred citation management software (EndNote, Refworks, etc)
  • Provide basic guidance on screening process
  • Provide researcher with several documents to include in publication (partially completed PRISMA flowchart, Citation Data Tracking, and search strategies)
  • Assist in writing Methods section for publication
  • Instruct how to obtain full text of articles through ILL if necessary
  • Run update of searches prior to publication (as required by standards)
  • At least 5 meetings required (once a month recommended)
  • Librarian listed as contributing author is required for this option

Systematic Review Assessment

Make sure you review and complete the Systematic Review and Assessment forms before meeting with the Librarian:

Intro to Systematic Reviews

Here is a powerpoint presentation that provides a brief overview of Systematic Reviews presented at the UTHealth School of Public Health on by Amy Taylor, Liaison Librarian at the Texas Medical Center Library

Data Sources and Additional Resources

Documenting Your Search Strategy