Literature searches for systematic reviews have certain qualities which are aligned with the overall methodology of a systematic review. These qualities are explained below. 

• Comprehensive
  • Multiple bibliographic databases should be searched, including Ovid MEDLINE, Ovid Embase, and Cochrane Library (CENTRAL). You should also search more specialised databases relevant to your research area, e.g. Ovid Emcare for nursing and allied health topics or PsycINFO for mental health. See section 4.3.1 of the Cochrane Handbook.
  • In addition to database searches, use methods such as hand-searching (manually searching through key journals); forwards & backwards citation searching; and if necessary, directly contacting authors to e.g. request a manuscript or request missing data.
  • For systematic reviews of interventions, relevant unpublished data should also be captured, e.g. unpublished trial data. These types of data are known as grey literature. For advice on searching for grey literature, see our Grey Literature Guide or attend our grey literature webinar.
• Sensitive (rather than precise)
  • The search is designed to be highly sensitive in order to capture all relevant literature. A highly sensitive search returns exponentially more results than a precise search - the review team may need to screen several thousand search results. 
  • Precise database searches may, for example, search for keywords only within the title and abstract fields. In contrast, a sensitive database search strategy may look for the same keywords within all fields. Read more about the implications for your search strategy in our Literature Searching Guide > Develop question > Comprehensive vs targeted.
  • Accordingly, you must justify any language or date limits applied to the search. Any limits should be related to the eligibility criteria set out in your protocol.
• Transparent and reproducible
  • Keep a record of the final search strategies for each database searched, along with details such as the search dates and how many results were included from each database (see Reference Management section below). Enough detail should be provided that other researchers could replicate your search in its entirety. See items 6 and 7 on page two of the PRISMA 2020 expanded checklist for more information on what to document.
  • On completion of the systematic review, full search strategies will ideally be included in your final manuscript - see Reporting Findings for details. Note: To save space in your manuscript, you can also deposit a file containing the search strategies into the Monash Health Research Repository and then simply include the URL in your manuscript. For more information contact the Library team via library@monashhealth.org.
• Up-to-date 
  • To ensure the currency of your findings, the final searches should be completed within 6 months of publication. If more than 6 months have passed since the last search and your systematic review is still in-progress, you will need to re-run your searches to check if any new relevant studies have been published.

The following resources will help you to plan and execute your literature search in line with the principles above: 

• Literature Searching Guide
  • Including our step-by-step guide to performing an advanced search in Ovid MEDLINE
  • 1-page overview of health databases
• Advanced Literature Searching webinar
  • To attend live, check the Library's webinar calendar and register for a session.
  • To view it on-demand, watch the recording on Latte.
• Citation searching or citation mapping
  • Watch a recording of our webinar on citation mapping tools in Latte.
  • 1-page matrix of citation mapping tools
• Artificial intelligence (AI) tools
  • 1-page matrix of AI search tools
  • Watch a recording of our webinar on AI search tools in Latte.
  • Read more about the use of AI and technology in systematic reviews.
• Grey Literature Guide

Note: Best practice is to consult a librarian while developing your search strategy - see Library support below.

It is not uncommon to start with hundreds or thousands of results. There are some important steps involved in managing results when conducting a systematic review.

1. Export search results from a research database to your reference manager

Exporting results to a reference manager helps prepare for later stages of your research, such as screening and writing.

• Search results can be exported from all major databases and in a variety of file formats such as: RIS, BIBTex, EndNote, Excel.
• See our 1-page summary of how to export search results from Ovid (Medline, Embase, Emcare, and APA PsycInfo), Cochrane Library, and ProQuest Nursing & Allied Health.
• More details on exporting results can be found in the Manage results guide 

2. Document search result numbers 

Make sure you document the total number of records identified from each database before deduplication.

• The PRISMA Flow Diagram requires identification of the number of results from each database your have searched. 
• Create groups in your reference manager for each database searched, to easily identify the total number of records from each database. 

3. Deduplication

There will be a number of duplicate studies among your search results, due to some similarities between the journals covered by citation databases. It is important to:

• Remove duplicates before the screening stage. 
• Document how many duplicates have been removed as required by the PRISMA Flow Diagram

Many reference management programs include a deduplication tool. Covidence also has an automated deduplication function which tracks the number of duplicates removed. See #5 below for or visit the Covidence guide for more information. 

4. Sharing references among the review team

When working with other researchers on a review, you may want to share your reference manager library. The team can then view search results, access pdfs and create citations during the wring process. 

Most reference managers have a share function. For example, in EndNote you can add email addresses of the people you want to share citations for your entire library, or a specific group in your library. Select whether to grant Read & Write access or Read Only access.

5. Moving studies from your reference manager to your systematic review software for screening

One of the best tools for screening results is Covidence. Monash Health has an institutional licence for Covidence and can provide support with using this tool.

• You can move your studies from your reference manger into Covidence - Find out more
• See our Covidence guide for more information.

Use a reference manager

We highly recommended using reference manager software as you may be dealing with thousands of results. Using software helps:

• Document and save search results
• De-duplication
• Share literature results with members of your team
• Citation and creation of a bibliography during writing

Commonly used reference management software include:

• EndNote - Available on all Monash Health Library PCs
• Zotero - free to download
• Mendeley - free to download
• Paperpile - subscription based

More information on other reference mangers is available via the referencing information guide. 

Rerun a search

Sometimes you may need to rerun your literature search because your search is older than 6-12 months old. Systematic review manuscript submissions with a search older than 12 months may be considered out-of-date and ineligible for submission. See Cochrane section 4-4-10 for more information. Another reason to rerun a search is if you are updating a previously published review. 

Rerun a database search 

The aim of rerunning a database search is to find newly published studies or older studies that have been recently added to the database since your last search. The table below has set commands that identify papers in set date ranges. 

Note: If it has been longer than 12 months consider re-checking your subject headings as they may have been updated or new subject headings added. MeSH is updated annually.  

* Not accessible via Monash Health. May be accessible via a university affiliation

Adapted from source: University of SA Library- https://guides.library.unisa.edu.au/SystematicReviews/UpdateASearch

At this stage of your systematic review, the Library team can support you by: 

• Reviewing your draft search strategy and providing feedback, either informally or via completion of a PRESS checklist.
• Meeting with you and/or your team to discuss your review and offer guidance on using databases such as Ovid Medline.
• Providing guidance on reference management.

For an overview of Library research support services, click the link below.

Overview of Library Research Support Services

Requesting Library support

To request research support from the Library, submit the online request form linked below.

Request research support

The highest level of support offered to Monash Health systematic review teams is at the co-authorship level. More information about co-authorship support is provided within the above form -- simply select the option for Request librarian joins the review team as a co-author to learn more.

Students

Health professional students who are affiliated with Monash Health can also access research support - see our service matrix for more information. Requests can be submitted via the same research support request form.