Planning A Systematic Review

The Importance of the Protocol

A systematic review is designed to answer a focused health sciences related question in a systematic, reproducible matter. To achieve this goal, researchers should create a Protocol.

A protocol is a document designed to guide researchers through the complete systematic review process. Typically these documents serve as a guide for the research team throughout the life of the review.

 Below are various sections found in a comprehensive protocol. 

Team Members

While a systematic review team should have at least two members, a well-rounded team will include the following members:

  1. Subject matter expert
  2. Systematic Review methodology expert
  3. Evidence search expert
  4. Quantitative methods expert

The Woodruff Health Sciences Library Systematic Review Team can provide you with SR searching and methodology expertise.


Selecting the proper databases to search for the evidence is a key decision every Systematic Review team must face.  While health sciences databases such as PubMed (Medline) and Embase are essential to systematic review searching, subject-specific databases can provide you with relevant and timely evidence.


Subject Specific Databases

  • Life sciences
  • Biology
  • Microbiology
  • Biotechnology
  • Environmental studies
  • Biochemistry
  • Biophysics
  • Bioengineering
Cochrane Central Register of Controlled Trials (CENTRAL)
  • Controlled Trials
  • Nursing
  • Allied health
Education Resources Information Center (ERIC)
Joanna Briggs
  • Evidence Based Medicine
  • Psychology
Web of Science
  • Soci-economics
  • Biomedicine

Region-Specific Databases

Consider region-specific databases when your study question includes a special population.

Region-Specific Databases

African Index Medicus (AIM)
  • Africa
KCI-Korean Journal Database (WoS)
  • Korea
  • Latin America
Russian Science Citation Index (WoS)
  • Russia
ScieELO Citation Index (WoS)
  • Latin America
  • Portugal
  • Spain
  • South Africa
*WoS = Web of Science

Grey Literature

Grey literature is any documentation that might be relevant for your systematic review that typically isn't found in a database. Government documents, reports, white papers, news articles, dissertations are all types of grey literature.

Including grey literature in your systematic review will diminish publication bias.

Grey Literature sources

CDC Stacks Collection of CDC publications including guidelines and recommendations and MMWR reports. N/A is a database of privately and publicly funded clinical studies conducted around the world. 2000-present
Factiva International, national, and local news sources and news wires. N/A
Institutional Repository for Information Sharing (IRIS) The digital library of the World Health Organization (WHO)s published material and technical information. Its content is freely accessible and searchable in the six official languages (Arabic, Chinese, English, French, Russian & Spanish). 1948-present
National Technical Reports Literature (NTRL) Access to a large collection of historical and current authenticated government technical reports in a wide range of subject areas, including health care, environmental pollution, medicine, biology, and engineering. 1964-present
Nexis Uni Access to news, business, medical, educational and legal sources. The sources include international, national, and regional newspapers; magazines; trade journals; newsletters; wire service reports; and transcripts of television and radio news programs. 1789-present
ProQuest Dissertations & Theses The official digital dissertations archive for the Library of Congress. 1861-present
WHO International Clinical Trials Registry Platform (ICTRP) The main aim of the WHO ICTRP is to facilitate the prospective registration of the WHO Trial Registration Data Set on all clinical trials, and the public accessibility of that information. N/A

Limiting Your Search

Consider these limits when writing your protocol.

  • Time Period
    • (Ex. Last 5 years, 2000-2010)
  • Study Populations
    • Consider age ranges as well as special populations.
  • Humans only
    • Are there any studies that might feature both humans and animals?
  • National/International
  • Language
    • To avoid bias consider what languages your team members can read and review.
  • Study Methodology
    • Are you only interested in randomized controlled trials? Cohort studies?

Project Timeline

A project timeline should be established within your protocol. Below is a table of a typical Systematic Review timeline.

Cochrane's estimated timeline for completing a systematic review

Month Activity
1-2 Preparation of protocol
3-8 Searches for published and unpublished studies
2-3 Pilot test of eligibility criteria
3-8 Inclusion assessments
3 Pilot test of 'Risk of bias' assessment
3-10 Validity assessments
3 Pilot test of data collection
3-10 Data collection
3-10 Data entry
5-11 Follow up of missing information
8-1 Analysis
1-11 Preparation of review report
12- Keeping the review up-to-date
*Cochrane Handbook for Systematic Reviews of Interventions


Higgins J.P.T., Green S. (editors). Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0 [updated March 2011]. The Cochrane Collaboration, 2011. Available from

Institute of Medicine. 2011. Finding What Works in Health Care: Standards for Systematic Reviews. Washington, DC: The National Academies Press.