Boolean Operators ( AND, OR, NOT) are commands used to make your search strategy more concise. In it's most simple use, library databases are searched effectively by linking two keywords with a Boolean Operator. This page covers AND, OR, NOT in both simple and advanced searches. For advanced searches, Boolean Operators are combined with symbols and Order of Operation to create Nesting. Nesting examples are included on this page but will also be covered in this advanced section under the tab "nesting."
Use "AND" to link two terms together, this narrows your results. Articles will contain both and omit the pieces that only have one term or the other.
When you start to nest Boolean terms, AND is seen as the primary operator, and will be factored before OR and NOT.
An example of AND would be these different searches:
*Results run as a Pubmed search on 4/6/2021.
Use "OR" to look for articles that contain both words. This generally broadens your results; articles will contain either term or both terms. Used with nesting, such as quotations, this strategy can help narrow a broad result.
OR can be seen in the AND example box on this page but here is another one:
*Results run as a Pubmed search on 4/6/2021.
Use "NOT" to look for articles that do not contain a specific word. This narrows your results.
Using NOT may negatively effect your results, as it ignores all articles with the undesired word. This operator is best used after you have gained some familiarity with the literature and notice a topic trend you wish to ignore, or if you already know you do not wish to look at a particular portion of the literature.
An example of NOT in action* would be:
*Results run as a Pubmed search on 4/6/2021.
Created by Tiffany Follin using Piktochart.
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