Boolean Operators

Boolean Searching: A search technique that uses Boolean Operators (AND, OR, NOT) to limit or widen your search.

Boolean operators define the relationship between your search terms, allowing you to refine and focus your results.

• AND narrows your results by linking two terms together
• OR widens your results by bringing up results that have one term or another or both
• NOT restricts your search by excluding the term directly following it - it's a great operator to use if your search is retrieving a lot of irrelevant results!

Use Parentheses Effectively

Expert database searching that maximizes sensitivity and specificity for effective precision aka accuracy requires complex search phrases. Databases, in general, interpret a search string from left to right. In order to have greater control over the search to ensure that keywords are combined accurately, you must use parentheses to combine terms using Boolean Operators. So, how?

1. Brainstorm similar keywords related to Concept A, ensuring that they meet your requirements for bringing back resources on Concept A. 
2. Combine each of these using OR.
3. Add parentheses around this entire search phrase.
4. Repeat steps 1 - 3 for each other Concept (Concept B, Concept C, etc.)
5. Finally combine each of the separate Concepts using AND between each set of parentheses.

Further details in Foundational search skills tab

Where to get information on how to search a specific database?

While Boolean Operators and parentheses are relatively universal rules across databases, each database has it's own syntax rules. So where can you go to get details on what a types of material a database includes, how to search within that database, and more? Go to the Help section. For example, PubMed has an in-depth NCBI PubMed Help Manual and online tutorials. Need help with Scopus? Use Scopus' Help guide.