Boolean Logic
AND: Is used to find to records including all the terms. Using AND is helpful when narrowing your results. For example: undergraduates AND mental health AND counseling
OR: Is used to find any records with synonyms/related terms. This is helpful for broadening your results. For example: undergraduates OR college students OR freshmen OR university students.
NOT: Is used to exclude records. This is helpful for narrowing your results for relevancy. For example: Undergraduates NOT freshmen
NEAR/x or Nx: Is used to find records in which the keywords are separated within a certain, specified, number of words from each other. You must specify the number or X variable. I recommend 5. For example: breast NEAR/5 cancer. Or tax N5 reform. You cannot use NEAR/x in conjunction with AND. Ebscohost databases use Nx.
Most databases adhere to the following order of preference for boolean logic:
- Nx or NEAR/x
- NOT
- AND
- OR
However, you can use parenthesis to group your logic and override the preference order. For example: (undergraduates OR college students OR university students) AND mental health.
Search Operators
" " - Use quotation marks to search for phrases or exact terminology. For example "incarcerated youth" will tell the database to only provide results for those words directly next to each other instead of any article that has incarcerated and youth in the text.
* - Use asterisk to truncate your results which will broaden your search to include various word endings and spells. For example: Child* will pull up results that include child, children, childrens, childhood. Some databases vary in the symbol they use for truncation - look at the databse or journal's help section to see what symbol (!, ?, or #, etc) they use.
? - Wildcarding allows you to substitute a symbol for one letter of a word in order to find different spellings. For example: wom!n = woman, women. Colo?r = color, colour.
Natural Vs. Controlled Language
Natural language tends to be the words you use colloquially. These might be "jargon" terms for your area of study and words you, or authors, use to describe their research questions. However, databases have their own terminology and they categorize/label each article according to this standard language. This language does not always match the terminology common in the field or that authors list at their keywords. These are called subject headings, MeSH headings, etc. Watch the video below for help finding the controlled vocabulary for your topic.
