Boolean Logic

Boolean operators--OR, AND, NOT--are used between search terms to combine concepts in a more precise way than is possible with keyword searching. See also Combining Terms in the Library Catalog (CLIC) for additional explanation.


Boolean OR


The OR operator broadens a search, retrieving records that contain either term, but not necessarily both. It is used to combine synonyms or related concepts.


 EXAMPLE:  anorexia OR bulimia


Boolean AND


The AND operator narrows a search, retrieving only records containing both term(s). AND is used to narrow a topic to a specific aspect.


EXAMPLE:  (anorexia OR bulimia) AND "college students"


The NOT operator also narrows a search by removing all records that contain a particular word or phrase.
EXAMPLE: anorexia  NOT bulimia


The NOT operator is rarely used. It often screens out useful records.