Research Guides: PubMed @ NYU: Boolean Searching

Boolean Searching

Link to examples:

Boolean logic uses the operators AND, OR, and NOT to connect search terms when using catalogs, databases, or a web search tool.

A simple search on: handwashing retrieves article citations containing that term.

A simple search on: handwashing AND hospital acquired infection retrieves citations containing BOTH terms.

For this research question: Does handwashing among healthcare workers reduce hospital acquired infection?

the main concepts are:

the Problem: hospital acquired infection

the Intervention: handwashing

Combine the two terms for a preliminary search.

BOOLEAN OPERATOR	SEARCH STATEMENT	RETRIEVES
AND	hospital acquired infection AND handwashing	Retrieves citations with BOTH terms present
OR	hospital acquired infection OR cross infection OR nosocomial infection	Retrieves citations with EITHER/ANY of the terms present (OR is used to string synonyms together; remember, OR retrieves MORE!)
AND, OR	(cross infection OR nosocomial infection OR hospital acquired infection) AND handwashing	Search sets may be combined. This search locates citations with the word handwashing AND (ANY one of the terms combined with OR)
AND, OR	(cross infection OR nosocomial infection OR hospital acquired infection) AND handwashing AND Publication type: randomized controlled trial	Retrieves citations with the word handwashing AND (ANY one of the terms combined with OR) AND limited to articles with the Publication type: randomized controlled trial. (This is one example of using database Limits.)
NOT	handwashing NOT masks	Retrieves citations with the term handwashing, but omits records with the term masks (Caution:* the NOT operator should be used sparingly and carefully as it may omit citations relevant to a search.* For example, an article about handwashing that includes the word masks might be relevant to a search on handwashing.)

A SAMPLE RESULT FROM Medline/Pubmed:

Boolean logic uses the operators AND, OR, and NOT to connect search terms when using catalogs, databases, or web searching.

A simple search on: driving retrieves article citations containing that term.
A simple search on: driving AND mobile phone retrieves citations containing BOTH terms.
A search combining terms with AND and synonyms with OR is shown below, to answer the research question:

Is there evidence that the use of a mobile phone while driving increases the incidence of accidents?.

BOOLEAN OPERATOR	SEARCH STATEMENT	RETRIEVES
AND	driving AND mobile phone	AND narrows your search results to citations with BOTH terms present.
OR	mobile phone OR cell phone OR text messaging	OR broadens your results to include citations with EITHER/ANY of the terms present. OR is used to string synonyms together. Remember, OR retrieves MORE!
AND, OR	driving AND (mobile phone OR cell phone OR text messaging)	This search locates citations with the word driving AND (ANY one of the terms combined with OR). The area where all 3 circles overlap represents search results with all criteria.
NOT	driving NOT cycling	Retrieves citations with the term driving, but omits records with the term cycling (Caution: the NOT operator should be used sparingly and carefully as it may omit citations relevant to a search. For example, an article about cycling might also be relevant to driving.)