Developing Effective Search Strategies

Combination of Search Terms

Most researchers know that the terms AND, OR, and NOT are used to combine terms (you may be familiar with their formal name of "Boolean operators" or "Boolean logic").  However, it is common for beginning researchers to apply them incorrectly when formulating a search statement.  Improper use of  AND, OR, and NOT is the second largest cause of a failed search. This is how these terms should be used:

• AND narrows the search so that all search terms must be included in each of the search results.
• OR expands a search to include any single one of your terms in the search results. OR is best used for synonyms or similar words.
• NOT eliminates unwanted search terms.

The chart below illustrates some examples of these terms "in action."

A Comparison of Three Search Terms: And, Or, and Not
Search Statement	Results
online teaching and  higher education	narrows the search results by eliminating online teaching in elementary or secondary schools
higher education or college or graduate programs	expands the search results by using synonyms for the concept of higher education
higher education not graduate programs	narrows the search results by eliminating 'graduate programs'.   CAUTION: "NOT" can often eliminates results that are desirable.  For example "Anorexia NOT males" will eliminate articles that mention BOTH males and females].

Now, to see how this all works in practice, click on the "Next" link (below) to take a look at constructing actual search statements.

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