Boolean operators allow searchers to customize how search operates
Although I am using capital letters to make these operators easy to find that is not needed
The three basic Boolean operators are
AND
OR
NOT (expressed as % in both Westlaw and Lexis, expressed as AND NOT in Lexis, expressed as NOT in Bloomberg Law)
AND
The AND function requires an additional term to be in the document.
It serves to narrow the search.
For example the search “Warranty of Habitability” AND “Covenant of Habitability” will find fewer matches than just “Covenant of Habitability.”
OR
The OR function allows the search to find other matches.
It serves to broaden the search.
For example, the search “Warranty of Habitability” OR “Covenant of Habitability” will find more matches than either phrase alone.
NOT
The NOT function allows the search to exclude results with certain terms
It serves to narrow the search.
For example, the search “Warranty of Habitability” NOT “Covenant of Habitability” will find fewer results than simply “Warranty of Habitability.”
NOT in both Westlaw and Lexis is expressed %.
NOT in Lexis can also be expressed AND NOT.
NOT in Bloomberg is expressed NOT, AND NOT, BUT NOT