Whenever you conduct a search in a search engine ordatabase, you typically type in whatever you’reinterested in—then the search engine or database givesyou the results of your search. This is how Googleworks—it’s also how you search for books and articlesin library catalogs and library databases.Boolean operators let you better control what sorts ofbooks or articles will appear in your search results.Even more than this, Boolean operators are a helpfulway of conceptualizing your search. Once you’velearned how Boolean operators work, your search skillswill improve, whether that’s in a library database orGoogle.
Understanding Boolean Operators and howthey work is useful for a couple of differentreasons: 1. Boolean operators make it easier to find the books and articles you need. 2. Boolean operators make your searches more exact and thus more powerful. By constructing more specific searches, you narrow in on materials related to your topic much faster.
So what are Boolean Operators? You’re probablyalready using at least a couple of them. Thebiggest three are:Now let’s look at how to use them when yousearch.
“AND” lets you search for items that include two or more search terms orkeywords. Both terms must appear in the article or book in order for thatarticle or book to appear in your search results. Here are a few examples: Jim AND Jill dog AND cat Olympics AND skiingTry visualizing an “AND” search like this:Searching just “Jim” will give you the firstcircle of returns. Searching just “Jill” Jillwould give you the second circle. Butsearching “Jim AND Jill” will only give Jimyou the shaded portion—ie, only theresults for where the two search termsoverlap.
Here’s another example of using “AND”Poverty AND Crime• Your search results will show only items containing both search terms. poverty crime• Blue shaded area represents search results.
“OR” lets you search two or more search terms at once. Unlike “AND”searches, only one of the search terms need to appear in a book or articlein order for that book or article to appear in your search returns. John OR Jim cat OR feline soccer OR footballTry visualizing it like this:Searching using “OR” gives youEVERY article or book thatincludes either of the two search Jimterms (or keywords). This sort of Johnsearch is great if you’re unsure ofwhich keyword to use—you canjust try both at once!
Here’s another example using “OR”:College OR University• Your search results will show items containing either of the search terms.• Gold shaded area represents search results (it’s all gold). College university
“NOT” lets you exclude books or articles from your search results that youknow won’t be useful. Here are a few examples: Bigfoot NOT truck forest NOT (tropical OR rain) Rock NOT geologyTry visualizing a “NOT” search likethis:If I’m interested in rock music and Isearch “rock,” I may get a lot of searchreturns that relate to geology,something totally unrelated to rockmusic. But I can get rid of all those geologyuseless geology search returns by rocksearching: rock NOT geology. Thismeans I have a lot fewer searchreturns to weed through.
Another example of using “NOT”Cats NOT Dogs• Search results containing only information on cats, but nothing on dogs. Cats Dogs• Purple shaded area represents search results.
Just to be clear, you don’t need to capitalize Booleanoperators in order for them to work. They’re onlycapitalized in this tutorial for emphasis.Also, the “AND” is assumed by some search engines anddatabases, meaning the search engine/databaseautomatically puts an “AND” in between each word in yoursearch anyway.Let’s look at two final operators, both of which can be veryuseful.
Quotation marks are extremely useful. As we mentioned before, searchengines and databases may automatically put an “AND” in between each ofthe words in your search string. So if you search… King of the hill…the database will actually search: king AND of AND the AND hillSo how do we only search for books or articles that include the full phrase“King of the hill”? We use quotation marks around the phrase: “King of the hill”Now only items that use the full phrase will appear in our search results.This is especially helpful with full names. If we searched Henry Millerwithout quotation marks, every article or book that includes the namesHenry and Miller will show up in our returns. By putting “Henry Miller” inquotation marks, we weed out the useless stuff.
The asterisk is also called a wildcard. It’s also called a truncation mark.This is an extremely useful Boolean operator, and it’s well worth learninghow it works. Basically, it acts as a substitute for any conceivablecombination of letters. Let’s look at an example:If I was interested in feminism in professional sports, I might try a searchlike this: feminism AND professional sports.Unfortunately, that search may miss a couple of articles I’d find really useful.Why? Because “feminism” would have to appear in any book or article inmy search returns. What if a great article exists in a database, but it usesthe word “feminist” instead of “feminism” in the article record? It might notshow up in my search returns.Instead, I might search: femin* AND professional sports.The asterisk (*) lets me search every possible ending to “femin” all at once.Another example: civil* would pull up “civilization,” “civilizing,” “civil,” andevery other word that starts with “civil”.
Now let’s create a few searchstrings using Boolean operators.
Question #1 “I want to find information about cloning humans.”To find information on this topic, you couldactually try a couple of different search strings.Here are two possibilities: Cloning AND human “human cloning”
Question #2“I want to find information about either BradPitt or his wife, Angelina Jolie.”Suggested search: “Brad Pitt” OR “Angelina Jolie”
Question #3“I want to find information aboutmummies, but not mummies in Egypt.”Suggested search: mummies NOT Egypt
Question #4“I want to find information about behavior incats.”Consider: Is there more than one search termwe could use to find cat-related information?Possible search: Behavior AND (cats OR felines)
Question #5“I want information on designing web sites, butnot on specific web design softwareprograms.”Consider: which software programs help you create web sites?Possible searches: “web site design” NOT (Dreamweaver OR “Front Page”) “web site design” NOT software