ENG 190: Research and Persuasion

Boolean Operators/Boolean Searching

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Boolean searching is a search technique which uses Boolean operators to help bring back search results faster and with more precision. The most common Boolean operators are AND, OR, and NOT. These are logic-based words that help search engines narrow down or broaden search results. 

AND

The Boolean operator AND tells a search engine that you want to find information about two (or more) search terms. For example, cats and dogs.This will narrow down your search results because the search engine will only bring back results that include both search terms.

OR

The Boolean operator OR tells the search engine that you want to find information about either search term you've entered. For example, cats or felines. This will broaden your search results because the search engine will bring back any results that have either search term in them.

NOT

The Boolean operator NOT tells the search engine that you want to find information about the first search term, but nothing about the second. For example, cats not dogs. This will narrow down your research results because the search engine will bring back only resources about the first search term (cats), but exclude any resources that include the second search term (dogs).

Uses

As with any search strategy, you may want to consider what Boolean operators/searching is most useful for and anything you should be cautious about when using this searching technique:

Most Useful For:

• Narrowing down or broadening your search results by connecting search terms together using logic
• Making connections between keywords or emphasizing relationships between keywords when searching

Cautions:

• May bring back too many, too few, or irrelevant results  if keywords are not carefully selected
• Not all databases handle Boolean operators in the same way (e.g. some support nesting, some databases support symbols like "&", etc.)

The library has many books and ebooks in our collection which can help answer your questions about boolean operators/searching. Check out the sample books and web resources listed in the FAQ: What is Boolean searching and how can I use it in library databases? for additional information or watch the video below: