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Searching for Systematic Reviews: Recording your search strategy and results

This guide brings together information and guidance on effective searching for journal articles and grey literature for those undertaking a systematic review.

PRISMA

PRISMA (the Preferred Reporting Items for Systematic Reviews and Meta-Analyses) 

Several extensions of the PRISMA Statement have been developed to facilitate the reporting of different types or aspects of systematic reviews. These include for Abstracts; Equity; Harms (for reviews including Harm outcomes); Individual Patient Data; Network Meta-Analyses; Protocols; Diagnostic Test Accuracy; and Scoping Reviews.

Reporting your search strategy

The PRISMA 2009 checklist states for '#8 Search' that you should "Present full electronic search strategy for at least one database, including any limits used, such that it could be repeated". These reported electronic search strategies normally appear in an appendix or as supplementary material to a published systematic review as they are too long to include in the main part of the systematic review. Some published systematic reviews only include a search strategy optimised for one database whilst others e.g. some Cochrane systematic reviews will publish the search strategies for all databases searched. We anticipate that the PRISMA update 2020 will include a more explicit request to report (amongst other things): “full search strategies for all databases, registers, websites”. It is not necessary to include the number of results for each search line (although this can be helpful if you are seeking feedback on the search strategy).

In many databases you can simply copy and paste the search strategy from the screen but you may also find that some databases allow you to download the search strategy (which may require less formatting than the copy and paste option).

For a search strategy on the Ovid platform (Medline, Embase, PsycInfo, Global Health etc) take the following steps:

1) Run the search
2) Select 1 reference (it doesn't matter what this is as you are only interested in the strategy itself)
3)Click to Export

4) Select Word as the download format and ensure the Include Search History tick box is ticked. Click Export.

5) Open the Word document to view the search strategy at the top. This can be copied and pasted into e.g. an appendix or used to send to a colleague for peer review or posted to the King's KEATS KLaSS Searching for Systematic Reviews Discussion Forum for feedback.

Exported Search strategy example

Ovid Search History Launcher

Ovid have now made available a way to run a search strategy that someone else has sent you e.g. from Medline, Embase, PsycInfo etc. The Search History Launcher is available on their website. You copy and paste the search history in (you will need to edit out search line numbers). It works on campus without having to enter a username or password.

This will be useful for:

  • sharing a search strategy with a colleague so that they can see your search, its results and adapt it. 
  • when using a published search filter to add to your own search e.g. to limit to UK research or only a specific publication type e.g. RCTs or qualitative studies.
  • when adapting a search strategy on a specific concept from another published systematic review.

Study Flow Diagram example

Examples of flow diagrams from published systematic reviews (see the PRISMA Flow Diagram for a template).

You will see the information recorded can differ even in Cochrane Reviews but the flow diagram can be a useful place to summarise what databases and other resources have been searched and the reasons why full text articles which were assessed have been excluded (as recommended by PRISMA).

Example 1:

From: Kew KM, Carr R, Donovan T, Gordon M. Asthma education for school staff. Cochrane Database of Systematic Reviews 2017, Issue 4. Art. No.: CD012255. DOI: 10.1002/14651858.CD012255.pub2.

Example 2:

Flow diagram example

From: Welsh EJ, Carr R. Pulse oximeters to self monitor oxygen saturation levels as part of a personalised asthma action plan for people with asthma. Cochrane Database of Systematic Reviews 2015, Issue 9. Art. No.: CD011584. DOI: 10.1002/14651858.CD011584.pub2.