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Systematic reviews

A brief overview of systematic reviews and resources to support producing one.

Recording the search

Each database used should have the following information recorded:

  • Name of the database
  • The database provider e.g. Medline via EBSCOHost - Platform or vendor for electronic databases
  • When the search was run - the date and the year
  • The coverage dates of the databases used, e.g. CINAHL (EBSCOhost, 1981 to present). The PRISMA standards state to include this information 'where it is provided' by the database
  • The full strategy used. If you have built your searches in a document as demonstrated in this guide then you already have the full search strategies saved, which can then just be presented in an appendix to your paper. If you have built your searches within the databases (not covered in this guide) then you will need to copy or export your searches from the databases. In this case it is preferable to reproduce the strategy with the minimum of editing. Removing the number of hits identified, for example, can introduce errors and hide genuine mistakes  (CRD Systematic Reviews handbook)

Examples: see Appendix 3: Documenting the search process

Saving your searches in the databases

It can also be useful to save your search strategies in the databases you use.

  • If you have built your searches within the databases (a method not covered in this guide) saving your searches will allow you to easily re-run them at a later stage. Saving your searches also allows you to create alerts so that you are notified when new papers are added to the database which match your search
  • If you have built your searches in a document as demonstrated in this guide you can easily re-run your searches by copying and pasting them into the databases. However you still might find it useful to save your searches in the databases to create alerts so that you are notified when new papers match your search, if you would like this
  • See our website for information on creating alerts

Working with search results

Systematic searching will require the collection of whole sets of results from databases to be reviewed. This part of the process needs to be planned as much as any of the other steps because the results will go through a number of screening stages to remove irrelevant and duplicate results. Using reference management software such as Endnote can help with organising and maintaining the search results. If using EndNote, the results for your systematic review project are best kept separate from your regular Endnote library. Set up a separate systematic review Endnote library. The Final steps section of this guide also contains some information on using EndNote for this process.

For information on accessing Endnote go the UQ Library Referencing software page.

Exporting results to EndNote

Instructions for exporting to EndNote referencing software:
Database name and Platform Process to export Maximum number of results at a time
PubMed * From the results screen select Send to Citation Manager
* In Selection choose All results on this page
* Select Create File
* This will create a RIS file that will be sent to your EndNote Library
10,000
MEDLINE via Ovid * At the beginning of the search results select the All box and the choose export option
* In the Export Citation(s) choose the RIS Format
* For Fields, select Citation, Abstract  the select Export
* The results will then be sent to EndNote as an RIS file
* For over 3000 results rather than using the All box use the range box to select up to 3000 and export the search result in batches of following number ranges
3000
Embase.com (Elsevier) * From the Results section select the Select number of items drop down that matches your search result number
* Then select Export which will present a RIS export option and select Export
* The next screen is a download screen. Choose Download.
* The results will be sent to EndNote
10,000 (500 without creating a personal account)
MEDLINE via EBSCOhost *From the results screen select the Share drop down.
*Choose the option below Export results which will state:
*Email a link to download exported results (number range)
*In the Export manager select E-mail a link to a file with citations in: Select the RIS option
*Add your email address to the E-mail to option
Select Send
*A compressed RIS file of results will be sent to your email
25,000
Cochrane Library (Wiley) * In the results sections click Select all & the Export selected citation(s)
* Then select RIS(EndNote) & check the include abstract box
* Click Download.
* Records Will be sent to EndNote as a RIS file
Unlimited
CINAHL via EBSCOhost *From the results screen select the Share drop down.
*Choose the option below Export results which will state:
*Email a link to download exported results (number range)
*In the Export manager select E-mail a link to a file with citations in: Select the RIS option
*Add your email address to the E-mail to option
Select Send
*A compressed RIS file of results will be sent to your email
25,000
Web of Science (Clarivate) * From the Search results select Export and choose EndNote desktop from the drop-down list
* Select the records range. there is a maximum of 1000.
*If your results are greater than 1000 you will have to choose batches. The first export is 1-1000, Then the next  would be the next range until complete. E.g. 1001 - 1867
*Change record content to Full Record
*Choose export
*The results will be sent to your EndNote library as a RIS file
1000

Scopus
(Elsevier)

* From the results screen choose Select All
*Choose Export at the top of the search results
* Change the option to the RIS Format
*Select Export
*This will send the results to EndNote as a RIS file
2,000
Informit databases * Cannot export set of records in Informit. Only one record at a time.
* Open the record by selecting it via the Title
* Select the Export Citations option
* This will default to a citation window with the APA format. Change this via the drop down to EndNote
* Use the download arrow below to export the file to EndNote
1

Deduplication of search results

Once all results have been retrieved via all of the database searches there will be a number of duplicate records which will need to excluded. There are several software tools which can perform the de-duplication process.  Most of the tools involve using reference management software such as Endnote to create an exportable file for use in de-duplication software.

De-duplication tools
Tool Required File format Notes
Covidence XML, RIS or PubMed Will find most duplicates, and is a software tool that can be used for all stages of screening for a review
SR Accelerator deduplication tool XML format Only used to identify duplicate records
Rayyan RIS Will find most duplicates, and is a software tool that can be used for all stages of screening for a review
EndNote

RIS, .nbib, multiple formats according database export

(Export citations in PubMed format as an .nbib file)

Will find duplicates, but still requires manual selection

Updating searches

Systematic review searches may need to be re-run before the finalisation of the review. The Cochrane handbook recommends searches for all the relevant databases should be re-run prior to publication, if the initial search date is more than 12 months (preferably six months) from the intended publication date.