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Boolean Searching: Basic & Advanced Searching with Boolean

This one page LibGuide explores Boolean Searching tips defines different types of Library Searches

Basic & Advanced Searching with Boolean

Boolean Searching Header

The key to being a successful online searcher & researcher is to learn, practice and use common search techniques that you can apply to almost any database, including library databases, online catalogs, and even search engines like Google. It is important to learn these so that you will be able to quickly retrieve relevant information from the various sources. The goal of the next few tabs is to explain some of the basic searching tricks and techniques that will enable you to create a more effective (and successful) search phrase. Remember when you search a database and do not get the results you expect, please use Ask-A-Librarian for advice.  We are happy to help you find what you need.

The Venn Diagram on the Right demonstrates the characteristics of Robots, Aliens & Zombies.  You can see where each group is in a colored circle and where each circle overlaps you have overlapping elements; Robots and Aliens both share Advanced Technology,  while Robots and Zombies share No Emotions, and lastly Aliens and Zombies share a Taste for Flesh.  What they all have in common,  seen in the center most area is a desire to end Humans.  Searching Aliens AND Robots your results will be filled with the shared topic of Advanced Technology. Searching Aliens AND Robots AND Zombies will result in Death to Humans

**DISCLAIMER** Databases and search engines vary and may use portions of Boolean Searching. This information sheet is general tips & tricks and is meant to help in general use. Check the specific database or search engine (use the help screen) to see the operators it uses. 

George Boole, was an English mathematician, educator, philosopher, and logician who wrote about a system of logic designed to produce better search results by formulating precise queries. He called it the "calculus of thought." From his writings, we have derived Boolean logic and its operators: AND, OR, and NOT, which we use to link words and phrases for more precise searches.

Boolean searching is the most powerful way of searching a computer and may be used in many of the library's electronic databases, the Internet (Google) as well as the Library Catalog. Boolean searching uses three "operators" to combine your keywords into a more powerful and direct searches.  The basic Boolean operators are AND, OR and NOT. The operator you choose to combine keywords determines how the computer performs the search and what information it returns. Capitalizing the Boolean operators is not necessary in all databases but is a good habit to have.

AND is used to tell the computer that your search results must include BOTH (or all) of your search words – the computer looks for all results that have both words you have connected by AND.    AND narrows your search results by combining keywords   AND can be helpful when searching for a broad topic that you want only a piece of such as Education AND Preschool. This will give you only "preschool education." AND has the effect of narrowing your results shrinking and focusing your topic.   AND is often (but not always) a default in Library Database such as Academic Search Complete, and is added behind the scenes in many search engines like Google.  AND is sometimes represented by a + sign.

Boolean search of the EBSCO for Crime and Poverty

For example: Searching Crime you would get 212,400 results while searching just Poverty gets 61,500 results. Searching Crime AND Poverty gets 2020 results.  The results are only about crimes that are related to poverty.

NOT - narrows the search by eliminating words – the computer looks for results in a topic and then eliminates a portion. This is helpful to direct your research away from a topic or area such as Hurricanes NOT Texas This will return results about hurricanes in all states and countries except Texas. NOT is used to tell the computer that you do NOT want a search term in your results; that is, it excludes results.  NOT can be used to reduce the scope of a topic by removing or ignoring elements of a topic, such as a group (School NOT College) or an implied topic.  It can also help clarify your topic (New York NOT New York City). Occasionally the NOT command is represented by the - sign.

EBSCO Boolean search NOT dementia NOT alzheimers

For example: Doing research on Dementia but you do not want to include the topic of Alzheimer’s  you would search Dementia NOT Alzheimer’s to receive all of the information regarding Dementia that is NOT related to Alzheimer’s.

*NOT is a very powerful operator that should be used with caution.

OR - broadens the search by offering more choices – the computer looks for all results that have either the first word OR the second. This is helpful when searching for a topic that has several names or terms associated with it such as "skin cancer" OR Melanoma. This will return entries with either skin cancer or Melanoma as key words. OR is used to connect related or synonymous terms and is very helpful in searching ideas that can be described in different terms for example if you are looking for results that occur in America searching United States OR America OR USA OR U.S..   OR and a thesaurus can help you find more information about your topic. Keep in mind that names for things change over time and using a historic Term may get more results for example "Native Americans" OR "American Indians"

Screen Capture EBSCO boolean OR search Youth OR kids OR Children

For example: Children can also be thought of as Youth, or Kids in keyword searching the computer is literally looking for the word you ask for not the concept, so if you search for Kids you only get 104,170 results but by searching Youth OR Kids OR Children your results are 1,367,728, over a million more results.

When needing to do more advanced searching there are a few more tricks that can help you create more effective search strings.  The use of tools such as Exact Phrase (or the use of quotation marks), Wild Card and Truncation symbols, effective use of Nesting and the use of Proximity Operators are all more advanced searching tools that can assist you in creating successful search strings. For the most part web search engines like Google do not respond to the use of these more advanced searching techniques but they can be useful in the Library Databases.

 

**DISCLAIMER** Databases and search engines vary and may use portions of Advanced Searching. This information is general tips & tricks and is meant to help in general use. Check the specific database or search engine (use the help screen) to see the operators it uses. 

Quotation Marks or Phrases in Quotes AKA Exact Phrase 

Using "quotation marks" to enclose your search terms will force the computer to find your search string EXACTLY as you have it creating what is know as an Exact Phrase search. 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: “Microsoft Office” will only find results where Microsoft is followed directly by Office so it will not find an article with “in my office I use Microsoft” nor will it find “Office suite by Microsoft”.

Google excludes common words in English and in other languages it calls these stop words.  Words such as the, I,  “la” (which means “the” in Spanish) and “de” (which means “of” in French, Spanish, Italian, and Portuguese). When Google ignores a term critical to your search, e.g., LA (common abbreviation for Los Angeles), enclose the term in quotes.  

Nesting

Computers usually perform AND and NOT searches first, then the OR searches but like in a math equation you can force the computer to perform the OR search first with Nesting.  Nesting uses parenthesis () to encase the OR search string forcing the computer to complete the OR search first then move on to the AND or NOT search.

(Georgia OR South Carolina) AND "Teaching Shortage"

SO it first creates a large pool with the OR search then limits down the results with the AND or NOT search. The computer first searches for everything that has either Georgia OR South Carolina in it and then from that pool of results it finds items related to Teaching Shortages.

Boolean NESTING email OR e-mail OR electronic mail AND security

With this search people call electronic mail by several terms combining them in an OR search encased in parenthesis creates a pool of results that include all of the variations of terms for electronic mail and then it limits that pool to only those results that ALSO talk about security.


 

Wild Card and Truncation symbols

Searching using ? as a wildcard and * as a truncation symbol allows you to create searches where there are unknown characters, multiple spellings or various endings.  (Note neither symbol can be the first character in your search term). Generally speaking the ? replaces a letter such as wom?n will find women and woman.  The * is for truncation or finding all of the various endings a word could have so a search for work* will find all of the words that start with work but have different endings such as working, worked, workhorse etc.

Example: ski? OR ski* - other words that might be used in an article about "ski" are skiingskier, and skis. If you were to type skier, you would miss all the articles about skiing or people who like to ski. Thus, you should use only the root word in a search string, but also use a wildcard to indicate that you want articles with all other forms of the word in them.

Remember not to shorten the search term too much. Manufactur* will search manufacturingmanufacturermanufacturemanufactures.  Shorting Manufactur* down to Man*, you would receive information about manufacturing, but you would also information about management, manuals, mankind, manipulation, and people named Manuel, etc.


 

Proximity Operators

Proximity (aka positional) Operators are not really part of Boolean Logic, but like Boolean they help formulate search statements. Not all search engines or databases accept Proximity Operators so make sure to read the help screen for more advanced help.  N# (near) and W# (within) are Proximity Operators that will connect words together similar to using the “quotation marks”.  Using N# or W# followed by a number tells the computer you want the two search words to be found within a certain number of words of each other.

Within or W# searches for your two keywords in the order of your search string with a maximum number of words between them.

Example: repressed W8 memory will find articles that have the word repressed first with up to eight words apart from the word memory. Key here is that repressed is BEFORE memory.

Near or N# searches for your two keywords regardless of the order in which they appear and are separated but a maximum of words apart.

Example: tax N5 codes will find articles that have the words tax and codes a maximum of five words apart no matter the order in which they appear.

ADJ (or adjacent to) is a way to link words into phrases like quotation marks, it tells the computer that the keywords must be found next to one another but unlike quotation marks the words can appear in either order.  This can be helpful if you are unsure if an author is listed first name then last or the other way around.

Example: Ernest ADJ Hemingway will find both Ernest Hemingway and Hemingway, Ernest. 

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Types of Searches

Video from Douglas College Library British Columbia

Video from Santiago Canyon College