Boolean Logic for Keyword Searching

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Boolean Logic for Keyword Searching

• Southwest Virginia Community College
• LBR 295

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Introduction

• Keyword searching vs. single subject searching
• Keyword searching is based on Boolean logic
• George Boole - English mathematician

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Three Little Words

• AND
• OR
• NOT
• Much like Venn diagrams

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AND

• Narrows a subject
• All keywords must be in search results
• AIDS AND children

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OR

• Broadens a subject
• Either keyword must be in search results
• Babies OR infants

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NOT

• May also narrow a subject
• Eliminates unwanted terms in search results
• Penguins NOT Pittsburgh

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Some Other Elements to Keyword Searching

• Truncation
• Symbols
• ?
• Internal (wom?n)
• External (skat)
• Skat will result in skate, skates, skaters,
  skating
• Dont know the spelling?

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Other Elements (cont.)

• Nesting
• Use parentheses ( ) to keep ANDs and ORs apart

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Advanced Keyword Searching

• Using all elements
• (wom?n OR female) AND (college OR universit)
  NOT men

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Hands-On

• Volunteers
• Draftees
• Boolean Page