Every librarian knows their Boolean Operators. Knowing how to use “AND,” “OR,” and “NOT” are keys to searching digital data. Just to recap, “AND” combines terms to limit a search (ex. London AND “Buckingham Palace”) . “OR” broadens searches (ex. London OR “Buckingham Palace”). “NOT” removes ideas from a search (ex. London NOT “Buckingham Palace”). While not Boolean, enclosing phrases in quotations marks (” “) means the searcher is looking for an exact phrase instead of those two words anywhere in the document. These skills are not only useful when locating data, but are often the first information literacy skills taught to patrons, especially in K-12 schools and higher education.
What the non-librarians may not know is that databases sometimes vary how Boolean operators are used. Some require the letters all be lower case. Others use upper case letters (the original version of Boolean was all upper case). Still others might use symbols instead of words (ex. “&” for “AND” and “-” for “NOT”). Some might even recognize multiple variants. These variations can usually be located under the “Help” menu. Occasionally, you can find them in a sidebar on the advanced search menu.
However, most of the time these variations, when they occur, are not obvious and cause searches to be hampered because the operators will not work properly. Why? With almost everyone I observed at the reference desk–both patrons and the other librarians on duty–one normally defaults to using the lower case due to typing simplicity (usually, lower case does work in popular databases). It is only when someone knows differently that they can use the correct variation for a particular database or website.
Now imagine if the world’s largest and most popular search engine doesn’t follow standard Boolean operators. Is this possible? Guess, what? It is. Google does not use all the standard Boolean Operators. I was shocked to learn this when I took the Power Searching with Google class! Might that be why some of my past Google Searches were unproductive? It was.
Google recognizes “and” and “AND.” Also, if more than one word or phrase is entered into a search, it uses “AND” as the “unwritten” default to combine the ideas (for example, if you typed Buckingham Palace without quotes it assumes Buckingham AND Palace). It does recognizes “OR,” but not “or.” The reason? If a lower case “or” is used it assumes the word not an operator, but part of a phrase (for example, “to be or not to be”).
However, Google’s version of “NOT” is not the standard upper case. Does this mean Google uses the lower case version or the symbol version? If you picked the symbol version, congratulations! For “NOT”, Google only recognizes the minus sign (“-“) to exclude words or quotes-enclosed phrases and it must be placed directly in front of the word or phrase without a space. Again, “NOT” in either case is assumed to be part of a phrase and not an operator. Oh, how I wished I knew this sooner! Of all the variations, this caused the most Google searching harm. Before the Power Searching class, I just assumed Google was not programmed to search “NOT” except in the advanced menu.
Thus on Google, our London and Buckingham Palace search would look like this:
AND: London AND “Buckingham Palace” or London and “Buckingham Palace”
OR: London OR “Buckingham Palace”
NOT: London -“Buckingham Palace”
What do I hope someone gains from reading this? First, readers can understand how Google uses Boolean and not fall into the “NOT” trap. Second, I hope to being awareness to the fact Boolean can differ from place to place; users just need to check and see how the particular database or search engine represents Boolean Operators.
If it helps, here are the details for Boolean Searching for several major search engines. You will have to check a particular database yourself due to licensing issues.
- Google: “Operators and more search help”
- Bing: “Advanced Search Options”
- Yahoo!: “Tips for using Yahoo! Search effectively”
Also, you can see how these search engines use other operators, such proximity searching.
Did you find this helpful? Would you like more searching tips?