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Information Literacy Session 1: Search Tools and Strategies: Boolean Operators

ENG 102 Embedded Librarian Session: Keywords, Boolean Operators, & Search Strategies

Using Boolean Operators

After you have a list of keywords, you need to connect them with Boolean operators to search for results in a database. Boolean operators refer to the terms AND, OR, and NOT as they are used in database searching. The examples below address the theme of why some college students binge drink.


Use AND when you want to join your concepts together and retrieve ONLY articles that contain all of your keywords. In this case, the search for causes of binge drinking among college students will look like this:

Causes AND binge drinking AND college students 

The search will retrieve articles that contain the word causes, but only if they also contain the words binge drinking and college students


OR tells the database that what you want is any article that contains either one term or another one, regardless of whether or not they appear in the same article. Or will always work to broaden a search because it includes more words. It is best suited for use with synonymous words or ideas. It would not make sense to do a search for 

Causes OR binge drinking OR college students 

because any useful articles about all three of your keywords would be lost in a virtual haystack of millions of articles about one or two of the keywords but not the other(s). Instead, it might be extremely useful to search for: (explanation in parenthesis)

Causes OR reasons (synonyms)
AND binge drinking  
AND college students OR university students (synonyms

Such a search would retrieve any article containing either the word causes or the word reasons, but only if it also included the term binge drinking and only if it also contained the terms college students or university students


NOT indicates “I don’t want any articles that contain this word.” That is a useful strategy if, for instance, you want to isolate binge drinking from, say, drug use. For example:

Causes
AND binge drinking NOT drug use

AND college students

As you can see, this search is both powerful and specific. Library search systems are built on Boolean logic, so they adapt themselves effortlessly to your complex search strategies.

Also, keep in mind that this is a search strategy meant to answer a pretty simple question, namely what the causes of binge drinking among college students are. Academic and professional research tasks often require a much broader scope and call for stacking search strategies and synthesizing the results in order to derive new understandings about the topic. For example, if the above search strategy helps you understand that the problem of student binge drinking has five root causes, you might have to perform additional searches in order to craft solutions for each. After synthesizing the information, your paper could then propose a comprehensive plan for addressing the problems of binge drinking on campus. Thus, depending on the nature of the your class assignment, you might need to perform multiple searches. 

By the way, unless you become a librarian, a philosopher, or a database designer, you won't likely ever need to use the phrase Boolean operators in a sentence. But to do research you do need to know that Boolean operators are AND, OR, and NOT, and that they combine keywords in meaningful ways for searching for information.

Please go to the next page to learn more.