Skip to main content

Libguide, SELU Sims memorial library

Ask a Librarian
Hours

LS 102 Course Materials

Introduction to Information Research

Boolean Operators

Boolean operators are used to connect search terms in ways that narrow or broaden a search. There are three commonly used Boolean operators: ANDOR, and NOT.

"AND" Operator

The AND operator retrieves all records that contain all of the search terms. Thus, the AND operator narrows a search. Combining two or more terms with the AND operator requires that all the terms occur in the same record. For example, the following Venn diagram illustrates records containing Macaroni AND Cheese.

                                                                                 

 The area in dark shading indicates where Macaroni and Cheese “overlap.”

"OR" Operator

The OR operator retrieves all records that contain at least one of the search terms. The OR operator thus expands a search. Combining a set of terms with the OR operator requires that at least one term be present in a record in order to retrieve that entry. For example, a search for Macaroni OR Cheese retrieves all records containing one or both of those terms.

                                                                     

"NOT" Operator

The NOT operator excludes a term or group of terms from your search. A search expression such as Macaroni NOT Cheese requires that a record contain the first term “Macaroni,” but not the second term “Cheese.” The NOT operator should be used cautiously! If a document contains information on both terms, using a NOT operator might eliminate desired records from your set.

                                                                                       

 

 

Sample Research Question:  Are college students at a greater risk for Internet addiction?

List primary keywords and fill in across the top row with "AND" between the terms. 
Synonyms for those keywords go down with "OR" between the terms.

Example AND / OR Grid:

college students

AND

Internet

AND

addiction

OR

 

OR

 

OR

undergraduates

AND

web

AND

habit

OR

 

OR

 

OR

freshman

AND

online

AND

dependency

Boolean Operators (AND, OR, NOT)