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Systematic Review

Are you considering developing a systematic review on a topic, but unsure where to start? This guide will help you to get started.

Choosing Databases

  • MEDLINE: PubMed, Ovid, Scopus (includes Embase)
  • EMBASE:, Scopus (includes MEDLINE)
  • Cochrane Library
  • PsychINFO (Ovid SP)
  • Web of Science
  • Campbell Library (
  • LILACS  ( - South America, Central America, and the Caribbean
  • Grey Literature
    • Conference abstracts and Proceedings
    • Dissertations and theses
    • Library catalogs
    • Reports
    • Registered clinical trials and research
    • Research via Open Access
    • Hand searching

Literature search protocol

A key element of systematic reviews is that their search strategy be predetermined, rigorous and transparent. A record must be kept of databases searched and search strategy used.  A consistent method of evaluating search results for inclusion must be worked out and applied so as to avoid bias.

Some inclusion/exclusion rules to consider:


Questions to Ask

Advice from the Cochrane Handbook for Systematic Reviews of Interventions  (2011)

Type of Study

You should consider which types of study are most applicable to your research question.

 “Specific aspects of study design and conduct should also be considered when defining eligibility criteria, even if the review is restricted to randomized trials.”

Time Period

Will your review be restricted by year of publication, or is it important that you cover all years?

"Date restrictions should be applied only if it is known that relevant studies could only have been reported during a specific time period, for example if the intervention was only available after a certain time point."


Should you restrict to English language publications only?

"Whenever possible review authors should attempt to identify and assess for eligibility all possibly relevant reports of trials irrespective of language of publication. No language restrictions should be included in the search strategy."

Publication Type

Are you restricting your search by publication type?

"Format restrictions such as excluding letters are not recommended because letters may contain important additional information relating to an earlier trial report or new information about a trial not reported elsewhere."

Geographic Considerations

Are there any geographic considerations to include in your search strategy?

For example, if you were researching Chinese herbal medicine you would need to consult Chinese literature.

-- QUT (Queensland University of Technology): Higgins JPT, Green S (editors). Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0 [updated March 2011]. The Cochrane Collaboration, 2011. Available from



Documenting search strategies

Systematic reviews require a meticulous documentation of their search strategy to enable a possible replication of their search in the future and a clear assessment of their quality.

Search details which must be recorded are:

  • Sources searched, such as:
    • Databases (including the platform) e.g. EBSCO (platform) PsycINFO (database).
    • Hand searching a record of the source (for example, Conference proceedings, journal title) and years searched must be kept.
    • Grey Literature sources
    • Organizations or experts contacted.
  • The date the search was conducted and the period searched
  • Subject headings and keywords used
  • Search history, including the combination of terms and any restrictions applied such as Language.
  • Number of results retrieved for each search and combination
  • Total number of records retrieved
  • Duplicates identified

-- QUT (Queensburry University of Technology)