What Are Boolean Operators?
Boolean Logic
Boolean operators are terms you can use to narrow or broaden your search in a database, library catalog or Google Scholar. The three basic operators are: AND, OR, and NOT.
Why Use Them?
- To focus a search when you are using multiple terms
- To include synonyms for your search terms in order to find all variations
- To exclude terms not relevant to your search
Using AND (Narrowing)
How To Use AND
Use the operator "AND" in a search to:
- Narrow your results
- Tell the database that ALL the terms must be present in the search results
- TIP: Put phrases such as United States or college students in "" to tell the database you want those terms together in your search
Examples
Search String: Anxiety AND "college students" AND alcohol
The search above tells the database that you want each article in your results to mention ALL the search terms. This narrows your results because all the terms must be present instead of any articles about anxiety, or college students, or alcohol.
Search String: Racism AND elections AND "United States"
The venn diagram below demonstrates that AND is the intersection of all your search terms - thus it narrows your search.
Using OR (Broadening)
How to Use OR
Use the operator OR to:
- Broaden your search by telling the database that ANY of the terms can be present in your results
- To include synonyms or related concepts for your search terms
Examples
Search String: College students OR university students OR undergraduates OR graduate students
The example above will broaden your search because it will pull up articles with ANY of those terms present.
Search String: Feminism OR Gender inequality OR women's rights
Using NOT (Narrowing)
How to Use NOT
Use the operator NOT to:
- Narrow your results
- Exclude specific words or concepts from your search results
Examples
Search String: Participation AND Democracy NOT "United States"
This tells the database to pull up results about participation and democracy but to exclude any articles that are about participation and democracy specifically in the United States.
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