OR, AND, NOT

What are Boolean operators?

• OR
• AND
• NOT

Two important points:

• Concepts ≠ Words
• Words you use to search for your topic have a relationship with each other

How to start:

1. Think about the concepts that make up your topic
2. Brainstorm for words to express those concepts
3. Consider:
   synonyms, related terms, different definitions, words and names that have changed over time
4. Decide whether there are words you want to exclude
5. Think about the relationships among the words

OR

• includes any of the words
• all areas are included
• expands the search: broader, more results

AND

• must include all of the words
• only overlapping areas are included
• narrows the search: more specific, fewer results, higher percentage of useful results

NOT

• excludes specific words
• excludes areas, even excluding the area of overlap
• narrows the search: eliminates words you don't want to find, but can also eliminate some useful results

Tips

• Can combine more than 2 words
• Can combine more than 1 Boolean operator:
  use parentheses to separate each part and to keep related words together
  For example: (Confederacy OR South) AND ("African American" OR Black OR Negro)
• Can combine with other search tools, such as quotation marks around phrases
• Can use to revise your searches
• Can use on Basic or Advanced Search screens:
  See screenshots for sample search screens

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©2007 by Jessica Goodman

e-mail: jgoodman@slis.sjsu.edu

This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 License.

Credits: Venn diagrams from Wikimedia Commons.