Senior Project Research: Tips for Effective Searches

Boolean operators form the basis of database logic. They connect your search words together to either narrow or broaden your set of results. The three basic boolean operators are: AND, OR, and NOT (or the - sign).

Use AND in a search to:

• narrow your results, telling the database that ALL search terms must be present in the resulting records
• example: cloning AND humans AND ethics. In many, but not all, databases, AND is implied.You can search using phrases to make your results more specific. For example:  "college students" AND "test anxiety". This way, the phrases show up in the results as you expect them to be.

Use OR in a search to:

• broaden your results, telling the database that ANY of your search terms can be present in the resulting records
• connect two or more similar concepts (synonyms)
• example: cloning OR genetics OR reproduction

Use NOT (or the - sign) in a search to:

• narrow your search, telling the database to ignore concepts that may be implied by your search terms
• exclude words from your search
• example:  cloning NOT sheep (or cloning -sheep)

Truncation, also called stemming, is a technique that broadens your search to include various word endings and spellings.

• To use truncation, enter the root of a word and put the truncation symbol at the end.
• The database will return results that include any ending of that root word.
• Examples:
  child* = child, childs, children, childrens, childhood
  genetic* = genetic, genetics, genetically
• Truncation symbols may vary by database; common symbols include: *, !, ?, or #

Different databases interpret searches differently. A common variation is how databases recognize phrases.

• Some assume that words typed next to each other should be searched as phrases.
• Others automatically put a Boolean AND between your search terms, requiring that all the words be present, but not necessarily adjacent to each other.
• These searches can retrieve very different results.
• Using parentheses or quotes around search words is a common way to do phrase searching, but not all databases or search engines use them.
• Example:  "genetic engineering"