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.
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?
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 Controlled Vocabularies
Controlled vocabularies are a set of predetermined terms that describe specific concepts. You will find that many databases use their own controlled vocabularies (sometimes called index terms, subject headings, or a thesaurus). If you have heard of MeSH, this stands for Medical Subject Headings, and is the controlled vocabulary used in PubMed.
Databases that use controlled vocabularies employ subject specialists who review individual citations and add the appropriate controlled vocabulary terms to the citation that describe all of the concepts covered in the article. Using controlled vocabulary terms in your search strategy allows you to locate citations no matter what term(s) an author does or does not use, and helps account for spelling variations and acronyms.
Understanding Truncation
Understanding Boolean Operators
Understanding Limiters and 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
Search with Keywords
Keywords are the words used in an article title, abstract, or other text field in a database. Keyword searching, or natural language searching, is how most people search for information and is often sufficient for most people. Keyword searching is also useful when attempting to identify literature that may not have been indexed with controlled vocabulary terms.
It is good practice to search with both controlled vocabulary and keywords because:
If you want to be as comprehensive as possible, search with both controlled vocabulary and keywords.
Example: chronic kidney disease, chronic renal failure, CKD, CRF
Alternative Method for Finding Controlled Vocabulary Terms
Avoid Stop Words
In bibliographic databases, stop words are words that the database has been programmed to ignore in a search string or query. Stop words include of, the, is, at, which,and on.
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.
| Database | Controlled Vocabulary? |
|---|---|
| CINAHL | Yes, CINAHL Headings |
| The Cochrane Library | Yes, MeSH |
| Embase | Yes, Emtree |
| ERIC | Yes, Thesaurus |
| Global Health | Yes, Thesaurus (part of "Search Tools") |
| PsycINFO | Yes, Thesaurus |
| PubMed | Yes, MeSH |
| Scopus | No |
| Web of Science | No |
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