What's in this article:
- How to use Boolean logic to narrow your search
- Using the AND operator
- Using the OR operator
- Using the NOT operator
- Using Parentheses
Boolean operators help search engines use logic to limit, narrow, or broaden your search results in order to surface content that is most relevant to your search. To use them, Boolean operators must be typed in all capital letters.
Learn more about the AND, OR, and NOT operators, and how they work on JSTOR, below:
AND is the default Boolean operator, and using it will narrow your search results by telling the search engine to return results that have BOTH/ALL search terms present.
For example, when you search JSTOR for scholarly content using only the search term "unicorn," the search yields a very large set of results.
If, for example, you are interested in researching the claim that unicorns appear to maidens, you might refine this set of results further by adding the operator AND along with "maiden” to your "unicorn" search. This will decrease the number of results to review and help you more easily find a relevant article.
All 1,386 total results will include both the term “unicorn” and the term “maiden.”
Using the OR Boolean operator will expand your search results by telling the search engine to return results that have EITHER/ANY of the search terms present.
For exampe, if you wanted to expand your results to include texts that mention unicorns and include results that mention Pegasus as well, the OR operator would expand that search:
After using the OR operator, you will return an expanded list of results to review.
The OR operator also works well if you want to include multiple synonyms in the same search.
Using the NOT Boolean operator will narrow your search results by telling the search engine to exclude results that have a particular search term present.
If you are seeing too many results that are not relevant to their research, finding a common pattern or theme in those results in which you might exclude a term, might be helpful.
For example, if you were only looking for scholarship on magical creatures that mentions unicorns or Pegasus, but do not want to see any results that include tapestries, the following query would work:
This set of results is smaller than the previous one, and no longer includes any content that includes the word, "tapestry." Using NOT in queries let the search engine know that we are not interested in the subsequent terms of the search.
When your search query includes multiple Boolean operators, parenthesis are important to help the search engine group them in a way that is relevant for your research.
In the above example, (unicorn OR Pegasus) is a sub-query. By grouping the terms this way, you are telling the search engine which terms must be present and which terms are optional. This eliminates ambiguity for the search engine and ensures that in its results maiden must exist, either unicorn and pegasus may exist, but that the term "tapestry" should not exist.