Systematic reviews: How to search

Extensive online resources on how to search the literature

• Choosing which databases to search
• How to search:
  • Medline (Ovid) - do this first - includes key techniques relevant to most databases
  • Embase (Ovid)
  • Emcare (Ovid)
  • APA PsycInfo (Ovid)
  • CINAHL (EBSCOhost)
  • Cochrane Library (Wiley)
• Text mining - researching search terms for difficult topics
• Translating search strategies to other databases - Polyglot Search Translator
• Recording your search methodology
• Database years of coverage

Individual search tutorials for SVHM staff (login required): 

• 1 hour tutorials online or face to face in the library
• searching Ovid Medline with a topic of your choice
• can include information on record keeping for systematic reviews
• up to 2 brief (approx 15 minute) follow up consultations around review processes, Covidence etc

Please keep in mind that these tutorials are designed to teach you generic literature searching skills. With the exception of co-authorship, library staff do not design final search strategies for a systematic review which takes considerably longer to refine. Contact us to book a tutorial or find out more.

Perfect your search in Ovid Medline first

• If you know how to search the Ovid interface then you won't have a problem with Embase, Emcare and PsycINFO. This makes the process EASIER.
• Ovid Medline ALL = Pubmed. You do not need to search both.
• You may need to explore search terms using text mining if the topic is tricky
• Refine, test, refine, test, refine .... you will almost certainly go through multiple drafts before finalising your search strategy
• Do not move on to any other databases until you are completely happy with the Medline search. This will SAVE YOU TIME.

 Translate your Medline search strategy into other databases

• Ovid databases use the same basic syntax/commands eg .ti,ab. to search title and abstract
• Subject headings will be different in every database and need to be checked each time
• Use Polyglot Search Translator to change syntax/commands to databases on other platforms eg CINAHL (EBSCOhost), Cochrane (Wiley)

Record your methods as you go

• In a Word document record:
  • full database name eg Ovid MEDLINE(R) ALL 1946 to August 17, 2021
  • full search strategy
  • date searched and number of results in each database
  • total results from all databases before removing duplicates
  • total results from all databases after removing duplicates
• This takes very little time as you go, but is impossible to recreate later

Don't read all the results every time you search a database - get rid of duplicates first

• Scan the first 100 or so titles and abstracts in each database to make sure your strategy is relevant
• Export ALL search results from each database to Endnote
• Remove duplicates in Endnote
• Look at each record ONCE

Image by Helen Wilding

Can librarians approve search strategies for a systematic review?

With the exception of our limited co-authorship service, library staff are unable to develop or approve search strategies for systematic reviews. This is because development of a structured search strategy for a systematic review is time intensive and involves a large commitment. It generally requires:

• extensive background research into your topic
• consultation with the review team around how terms will be defined, and inclusion/exclusion criteria for screening
• text mining of a key group of papers to discover appropriate subject headings and search phrases
• exploration of MeSH Terms (in Medline) and other sets of subject headings eg Emtree (Embase), CINAHL headings (CINAHL) 
• extensive testing and refining of search strategies to ensure they are returning appropriate results

What feedback can librarians provide on search strategies?

Research librarians can be booked for:

• an initial 1 hour literature search tutorial on a topic of your choice - this covers general search processes in Ovid Medline
• up to two short (approx 15 minute) follow up consultations to provide general feedback on a draft search strategy created in Ovid Medline.

These consultations can cover:

• whether your strategy "makes sense" in a structural way
• that you have used Boolean logic (AND, OR, NOT) correctly to combine search concepts
• that you have included both subject heading and text searching
• that your search syntax is correct eg phrase.ti,ab.
• general feedback on next steps to explore - this may include referring you to online resources
• general questions on searching processes (although these will mostly be addressed in the initial search tutorial)

Please note that this feedback will be verbal. Due to time constraints we cannot provide written feedback on search strategies. 

What feedback can't librarians provide?

Without doing our own background research into your topic we cannot tell you if:

• you have missed appropriate subject headings in Medline or any other database
• you have missed relevant phrases or textwords that should be included
• there is a more efficient way to search your topic
• your search results are appropriate
• your strategy has been translated correctly into another database
• your strategy is complete or correct