Systematic Reviews: A How-To Guide

Write a Search Strategy

While it may be tempting to jump straight into your search, developing a strategy will save you time in the long run as it will help to ensure that you find studies relevant to your question. In general, it is recommended that you work with a librarian to help you design comprehensive search strategies. Contact UVic Libraries to request a consultation. 

1. Revisit your research question to structure your search.
   The best way to search is to first break your research question down into its main concepts. This is where using a framework, such as a PICO, is useful. Which framework should I use?

2. Brainstorm and gather synonyms for your research question's main concepts.
   Think broadly and abstractly!
   Consider:
   • Terms that have the same/close meaning
     • e.g. Hypertension vs High blood pressure
   • Terms that have different spellings or acronyms
     • e.g. Leukemia vs Leukaemia
   • Complex concepts described inconsistently
     • e.g. Long-term patient-reported satisfaction after contralateral prophylactic mastectomy vs surviving breast cancer: women’s experiences with their changed bodies
   • Umbrella terms and specific names
     • e.g. Sexually-transmitted infections vs herpes, genital warts, syphilis, gonorrhea, chlamydia
   • Keywords and database-specific “subject headings”
     • e.g. Cancer, tumor, tumour vs Neoplasms (MeSH Unique ID: D009369)
        
3. Revisit the databases selected for the review
   The databases you choose will depend on your research question and the disciplines in which relevant research may be conducted. Librarians can also recommend databases to search for a systematic review. Contact UVic Libraries to request a consultation. Check UVic's Library's database catalog for a full list of available sources across all disciplines. Because every database works differently, different databases use the same syntax. 
   
   Dalhousie Search Syntax Guide - A cheat sheet for common health sciences databases
   
   More information on this topic can be found in B. Translate Search Strategies (see below).
    
4. Construct the search string

   Writing a successful search string takes a knowledge of bibliographic databases. Several search techniques are common to a variety of licensed databases - subject headings, truncation, Boolean operators, and limiters. Depending on your topic, there may also be search filters available to apply to one or more databases. 

   Understanding Subject Headings

• Subject Terms vs. Keywords
• Introduction: What is MeSH?
• MeSH Database/Dictionary
• PubMed’s Secret Ingredient: Explosions 
• Yale's MeSH Analyzer

Understanding Truncation

• MIT Libraries: Truncation

Understanding Boolean Operators

• MIT Libraries: Boolean Operators

Understanding Limiters and Filters

• Boston College Libraries Using Databases: Limiting Your Results: Using Filters

Adapted and modified with gratitude from City University of London's Doing Post Graduate Research research guide and Dalhousie University's Systematic Reviews: A How-To Guide

Translate Search Strategies

Evidence synthesis methods require authors to search multiple databases, and not all databases accept the same search "syntax." Each individual database requires use of specialized search syntax, and therefore evidence synthesis search strategies must be 'translated' between databases.

When translating a search strategy from one database to another, you will have to make some changes to get comparable results. 

1. Tailor every search strategy to each unique database, because within every database there are vendor/interface differences (ex. OVID vs. EBSCO vs ProQuest), subject headings versus keyword-only (ex. MEDLINE vs.SCOPUS), peer-reviewed content only (MEDLINE:yes, CINAHL; no), and different controlled vocabularies (ex. Medline - MeSH vs. Embase - EMTREE vs. CINAHL - Headings).