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Legal Research Refresher: Quick Guide to Boolean Terms & Connectors

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What are Boolean terms and connectors, and why use them?

There are a few different ways to run a search of a legal research database. You might use natural language search to enter a few terms that describe what you’re looking for, or to ask the search engine a question (the same way you would phrase a question to a person).

Boolean search (also known as terms and connectors search) involves using a few specific words and symbols to tell the search engine specifically what you do and do not want it to return. You can use Boolean search when you want stricter control over the types of results you see — for example, if you only want to see cases that include 2 phrases, or cases that do include phrase #1 but do not include phrase #2.

(There is also a third way to conduct legal research, via document-based search. With Casetext CARA A.I., for example, you can upload a document from your litigation, like a brief or complaint, and the search engine will use that to understand what you’re looking for. Click here to start a free trial of Casetext to try running a document-based search.)

Where can I use terms and connectors?

Terms and connectors are supported by most legal research platforms, including Westlaw, LexisNexis, Bloomberg Law, and Casetext.

What are the options for Boolean terms and connectors?

ANDShows you results where both search terms appearfraud AND damages → This one might be obvious, but as you might guess, it will only show you cases where the word fraud and the word damages both appear. It will not show you cases that include only one of these terms.
ORShows you results where at least one of your search terms appears. You can use this to account for synonymscar OR automobile → This would show you cases that include either the word car or the word automobile (or both).
NOTExcludes cases that use the word after NOTinfringement NOT patent → This would show you cases that do use the word infringement, but do not use the word patent.
“ “Searches for an exact match of the quotations“Due diligence” → This would find you cases that search for exactly what’s in the quotation marks: the phrase due diligence (as opposed to cases where the word due and the word diligence both appear).
( )Groups search termsAppeal AND (verdict OR judgment) → This would search for cases which include the word appeal as well as one or both of verdict and judgment
*Wildcard — allows for different letters to fill where the asterisk isWithdr*w → This would search for cases that have any word with a letter where the asterisk is (e.g. cases that have either withdraw or withdrew)
!Root expander — allows for different endings to the wordInfring! → This would search for cases that have any word that starts with infring (e.g. infringe, infringement, infringed)
/nProximity search — looks for search terms within N words of each other (to use this search technique, replace n with the number of words)Investor /5 diligence → This would look for cases that have the word diligence within 5 words of the word investor.
/sProximity search — looks for search terms appearing within the same sentenceFees /s reasonable → This would look for cases where the word fees and the word reasonable appear in the same sentence as each other at least once.
/pProximity search — looks for search terms appearing within the same paragraphAdmissible /p warrant → This would look for cases where the words admissible and warrant appear within the same paragraph at least once.

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