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4) Find Journal Articles: Boolean Operators

A University of Lethbridge Library guide to finding journal articles.

What are Boolean Operators?

Boolean operators are used to define the relationship between search terms.

They can be used to broaden or narrow a set of search results, and to improve the relevance of those results.

Most search tools, including scholarly databases and Web search engines, offer Boolean search options. If you're not sure whether a particular database supports Boolean searching, check the Help page.

Boolean Search Basics

There are three common Boolean operators: AND, OR, NOT (it's best to capitalize Boolean operators because some search tools require it).

OR is used to join synonymous or related terms, and instructs the search tool to retrieve any record that contains either (or both) of the terms, thus broadening your search results.

The OR operator is particularly useful when you are unsure of the words used to categorize your topic or if information on your topic is even available. If you are retrieving too few records, broaden your search by adding a synonym with the Boolean Operator OR.

AND is used to join words or phrases when both (or all) the terms must appear in the items you retrieve.

This search query would return a much smaller set of records, and the items found would be more specific to your research question. If you are retrieving too many records, try adding another search term with the Boolean Operator AND.

NOT is used to exclude a particular word or combination of words from your search results.

If you are retrieving many records that are unrelated to your topic, try using the NOT operator to eliminate a word. This should be done cautiously, because as well as deleting the unwanted items, such a search will also eliminate records that discuss both the relevant topic as well as the unrelated topic.

Complex Boolean Searching

It is possible to perform complex Boolean searches in which more than one Boolean Operator is used. To do this, enclose the terms connected with OR within parentheses. For example:

"land claims" AND (indian OR native)

Using round brackets ( ) in a search statement tells the system the order in which to perform the search. Think back to doing math equations in school – the brackets work the same way in a database.

The brackets tell the computer that "Indian" and "Native" both represent the same concept. It looks for all records that contain either of these words, then finds which of these also contain the term "land claims". As a basic rule – always use ( )’s to combine words linked together with OR.

It's also possible to search for multiple synonyms using round backets and the OR operator. For example:

("comprehensive claims" OR "land claims") AND (indian OR native OR "first nations" OR indigenous)

Putting "double quotes" around a phrase will retrieve ONLY that exact phrase  without variation.


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