Boolean Operators
Use AND, OR, and NOT to narrow or broaden search results.
Using AND
- narrows results
- ALL terms must be in each search result
Note: in most, but not all, databases, the AND is implied. For example, Google automatically puts an AND in between search terms.
Example: renewable energy AND China
Using OR
- broadens results
- searches for ANY of the terms in search results
- connects similar concepts (synonyms)
Example: renewable energy OR solar OR wind
Using NOT
- narrows results
- exclude words from search
This operator is great when you notice your search term is used in different disciplines. You might use this example when researching peacekeeping in the context of interpersonal conflict but your search results in documents about international conflict.
Example: peacekeeping NOT United Nations
Adapted from SAIS Library, Johns Hopkins Univ. "Database Search Tips" Guide (no longer extant).
Nesting
Nesting is the use of parentheses to put search words into groups.Connect search terms in parentheses with AND, OR, or NOT.
Example:
success AND (education OR employment)
Search results will contain either:
- success AND education
- success AND employment
Nesting is often used when search terms have similar meanings:
Example:
education AND (employment OR jobs)
Phrase searching
Use quotation marks or parentheses around search words to search for a phrase. Otherwise most databases will find records that include both terms, but not necessary the terms as a phrase.
Examples:
"middle east"
"united nations peacekeeping forces"
"civil society"
Adapted from SAIS Library, Johns Hopkins Univ. "Database Search Tips" Guide
Database Search Fields
Records in library databases are made of "fields." Fields can help narrow your search.
Example of common fields in databases:
- author
- title
- journal title
- abstract
- publisher
- date/year of publication
- subject/descriptor
- all text (searches the full text, if available)
Improving Search Results with Fields
- Most databases automatically search by keyword (looking for the term anywhere in the record).
- Limit the field for a search term to narrow the results.
- Fields are usually in drop down boxes.
- If the database has a single search box with no drop-down menu, look for an "Advanced Search" option.
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Adapted from SAIS Library, Johns Hopkins Univ. "Database Search Tips" Guide (no longer extant).
Search Strategy Builder
Search Strategy Builder
The Search Strategy Builder is a tool designed to teach you how to create a search string using Boolean logic. While it is not a database and is not designed to input a search, you should be able to cut and paste the results into most databases’ search boxes.