Boolean Operators, Truncation & Wildcards Searching for Data

What is a Boolean Operator? Boolean Operators are simple words (AND, OR, NOT) used as conjunctions to combine or exclude keywords in a search, narrowing or broadening the search, resulting in more focused and productive results.

Why use Boolean Operators? Using Boolean operators can greatly reduce or expand the amount of records returned in a search. Boolean operators are useful in saving time by focusing your searches resulting in targeted results that are more appropriate to your needs. This should save time and effort by eliminating inappropriate hits that you need to scan before discarding them.

How to use Boolean Operators? AND—requires both terms to be in each item returned. If one term is contained in the document and the other is not, the item is not included in the resulting list. (Narrows the search) Example: A search on stock market AND trading could include results which contain: stock market trading; trading on the stock market; and trading on the late afternoon stock market.

How to use Boolean Operators? OR—either term (or both) will be in the returned document. (Broadens the search) Example: A search on ecology OR pollution could include results which contain: documents containing the world ecology (but not pollution) documents containing the word pollution (but not ecology) documents with ecology and pollution in either order or number of uses.

How to use Boolean Operators? NOT or AND NOT - in general the first term is searched, then any records containing the term after the operators are subtracted from the results. (Be careful with use as the attempt to narrow the search may be too exclusive and eliminate useful sources. Example: A search on Mexico AND NOT city includes results which contain: New Mexico; the nation of Mexico; US-Mexico trade; but does not return Mexico City.

Truncation Truncation or wildcard symbols can broaden your search and allow you to look for variations of words. For example, searching on sport* would bring up variations such as sport, sports, sporting, sporty, etc.  Most databases use an asterisk (*) for truncation and a question mark (?) as a "wildcard." However, some databases use other symbols – check the help page on databases if necessary

Truncation Use truncation to avoid having to think of (and type out) all possible variations of a word. To use truncation, enter the root of a word (the point at which the spelling could change)and put the truncation symbol at the end. The database will return results that include any ending of that root word. Examples: child* = child, childs, children, childrens, childhood genetic* = genetic, genetics, genetically migrat*= migrate, migratory, migration, etc.

Wildcards Similar to truncation, wildcards substitute a symbol for one letter of a word. This is useful if a word is spelled in different ways, but still has the same meaning. Examples: Wom?n = woman, women colo?r = color, colour