A Boolean search combines keywords with operators (AND, NOT, and OR) to produce more relevant results when you are searching.
Use AND to combine different keywords related to your topic.
Use OR to search similar terms (ex. teen OR teenager OR adolescent)
Use NOT to eliminate terms from your search (ex. yogurt NOT greek)
Most databases will allow you to search for exact phrases by placing the words in quotation marks. Without quotation marks to enclose a phrase, a search engine will insert the Boolean operator AND between distinct words, bringing back more results than necessary. Unlike using AND where your search results will include both words ANYWHERE in the results, using quotation marks is designed to find your search words as an exact phrase in the order you have typed it.
Example: A search for cost benefit analysis (without quotation marks) will you will get everything that mentions any of those words anywhere on the page (over 76,000 results comes back in Powersearch). Searching for "cost benefit analysis" (with quotation marks) will make sure the whole phrase appears intact in the results (with only ~73,000 results).
|Your Search String||What the Computer Searches||# of Results|
|cost benefit analysis||cost AND benefit AND analysis||~76,000|
|"cost benefit analysis"||cost benefit analysis||~73,000|
When using multiple Boolean operators and/or phrases, it is best to use parantheses to help the search engine know exactly how to conduct a search. Using parantheses will "nest" search terms together, like so:
((teen OR teenager OR adolescent) NOT "young adult") AND ("eating disorder" OR anorexia OR bulimia)
In English, this search string is looking for information on eating disorders among people ages 13-19.
When using a databases Advanced Search page, the separate search boxes may act as parentheses. Here's how this search might look two different ways within a database:
Basic search within Powersearch
Advanced search within Powersearch
Stop words are frequently occurring, insignificant words such as:
Because these words appear so often within records, articles, and webpages, they are often excluded by search tools to limit the amount of results brought back. Here's are some tips when dealing with stop words:
Some databases allow certain symbols to be used for searching multiple forms of a word. The Help section of any database will tell you if these symbols will work for searches in their databases.
Plurals -- A plus sign (+) added to the end of a word instructs the database to search for singular and plural forms of a word. Example: holiday+ retrieves holiday or holidays
Truncation -- An asterisk (*) added to the end of a root word instructs the database to search for all forms of a word. Example: house* retrieves house, houses, households, etc.
Wildcards -- A wildcard is a symbol used to represent any character. The pound symbol (#) is often used as a wildcard. Example: wom#n retrieves woman or women