Boolean search operators are words and symbols used to combine keywords in a search query to produce more relevant and precise results, making a search more efficient and targeted. They help include or exclude specific terms, search for exact phrases, and control the order of operations in complex queries.
The most common Boolean operators are:
AND
Retrieves results containing all the keywords joined by AND. It narrows down the search.
Use AND to combine keywords and narrow down results to only include items containing all the specified terms. For example, "climate change AND global warming" will return results with both phrases.
OR
Retrieves results containing any of the keywords joined by OR. It broadens the search.
Use OR to search for any of the specified terms and broaden your results. For instance, "renewable energy OR solar power" will find results with either phrase.
NOT or AND NOT
Excludes results containing the keyword after NOT/AND NOT. It narrows down the search by eliminating certain terms. Use NOT or AND NOT to exclude certain terms and narrow down your search, e.g. "energy NOT fossil fuels" omits results about fossil fuels.
" " (Quotation marks)
Retrieves results containing the exact phrase enclosed in upper double quotation marks. Use quotation marks to search for an exact phrase and exclude results with just individual words.
"Greenhouse gas emissions" returns that precise phrase.
( ) (Parentheses)
Groups keywords and operators to specify the logical order of operations. Use parentheses to group terms and specify the order of operations, e.g. (climate OR environment) AND policy searches for policy results containing climate or environment.
****** (Asterisk/Wildcard)
Retrieves results containing variations of the word stem, such as plurals or different word endings. This is also called "truncation". Use an asterisk to find variations of a word stem (e.g. plural forms).
Econom* returns results with economy, economies, economic, etc.
By combining these operators strategically, you can construct highly focused searches to pinpoint the most relevant results for your needs. Wildcards can be different in various resources.
Wild cards replace one or more characters in the middle of a word, e.g. “wom*#n” will find “woman or women”; behavi*#r” finds both English and American spellings.