2.3 | Boolean operators and phrase searching

Simple search dog.png
If your information smells like kibble, Search Tool Dog will find it (and probably eat it). (Image credit to Yen Verhoeven)

In module 1, we briefly discussed developing keywords from a research question. Here are some simple search techniques to use with your keywords. 

While you will learn more advanced search techniques in module 3, you should practice using Boolean operators and phrase searching now to hone your searching skills.

This game is Cy-pool approved. (Image generated by Copilot)

If you're a fan of X-Men Links to an external site. or the Marvel Cinematic Universe Links to an external site., try out this Boolean Operator game to gauge what you may already know about Boolean operators.

Make a note of what you got wrong or were unsure about. Read and take notes in the next section, focusing on those weak areas in your knowledge. 

Play the game!

Did you get them right??

Boolean1 operators (AND, OR, NOT) will help narrow or broaden your search.

Words that connect between two or more keywords in a search. The three primary Boolean operators are AND, OR, and NOT (in all caps).

Boolean operators must be capitalized for some search tools to recognize them, so it helps to capitalize them by default. Click the tabs to learn more about each operator. 

AND will narrow your search because it tells the search tool to find results that include all the keywords. 

Let's say you are researching the evolution of dogs. Your two keywords are dogs and evolution.

If you just Googled "dog," your millions of results include the latest news on dogs, the Humane Society, dogs on TikTok, Petfinder, Instagram dogs, and dog products on Amazon. 

And, if you just Googled "evolution," your millions of results include evolution definitions, Evolution Fresh (a juicing company), evolution in education, etc... 

 

When you enter dogs AND evolution, it tells the search tool to give you only results that include:

  • both dogs and evolution 

If you Google dogs AND evolution, you get the purple section, which includes sources like the PBS library on the Evolution of the Dog, a Scientific American article on how wolves became dogs, and Smithsonian Magazine's article on the origins of dogs from wolves. 

A Venn diagram showing the Boolean search, "dogs AND evolution."

You will not get any results that have:

  • only dog or
  • only evolution

So, results like the latest news on dogs, dog breeds, etc. (the red slice), or definitions of evolution, the movie Evolution, etc. (the blue slice) would be excluded from your search results.

The first field in Google Advanced Search performs like the Boolean AND:

A red arrow points to the field "all these words" in Google Advanced Search screen.

 

OR will expand your search because it tells the search tool to give you all the results including:

  •  all the results with just dogs and
  • all the results with just evolution and
  • all of the results with both dogs and evolution

It looks like this:

If you just Googled "dog," your millions of results include the latest news on dogs, dog breeds, the Humane Society, dogs on TikTok, Petfinder, Instagram dogs, and dog products on Amazon. 

And, if you just Googled "evolution," your millions of results include definitions of evolution, Evolution Fresh (a juicing company), the movie Evolution, etc... 

When you enter dogs OR evolution, the search tool will show you both sets of results:

The combination of all results with dogs and all results with evolution to represent "Dogs OR evolution."This may seem counterintuitive (since we are programmed to think the word "and" means more, which isn't true in this case). The way to remember it is:

OR means MORE

The "any of these words" field in Google Advanced Search performs like the Boolean OR:

An arrow points to the "any of these words" field in the Google Advanced Search screen.

  

NOT will narrow your search because it tells the search tool to exclude results with a certain keyword. 

For instance, if you take your millions of results for "dogs," the NOT evolution will now exclude (subtract) any results that include evolution, even if it has the word "dog."

When you enter dogs NOT evolution, the search tool will show you only the information in the red crescent:

Venn Diagram showing the Boolean search "dogs NOT evolution."This can be very useful for keywords that may have two meanings to them. 

The "none of these words" field in Google Advanced Search performs like the Boolean NOT:

An arrow points to the "none of these words" field in the Google Advanced Search screen.

  

You can manually use Boolean operators in the basic search box of most web search engines. Google and DuckDuckGo will let you use Boolean operators manually in their basic search box. 

For example, Google places an invisible AND between each of your search terms automatically when you use the basic search box. It will attempt to find results with all of your terms before anything else.

Boolean operators are incredibly useful, but each search engine may use them slightly differently, as you can see with these advanced search instructions for DuckDuckGo Links to an external site.. You may need to experiment with how and what terms you use with different search tools. 

 1 Boolean operators are named after George Boole Jr., an English mathematician, philosopher, and logician. 

Phrase searching is when you enter a specific phrase into the search box using quotations around it. It's useful when you want to find a specific term or phrase like "solar energy." 

A technique to indicate that specific words must remain in a certain order when doing a search. To indicate this, place quotation marks around the words you want kept together. 

The advanced search in Google has a space for phrase searching:

A red arrow points to the "this exact word or phrase" field in the Google Advanced Search screen.

Quotations around the phrase tell the search engine to search for those words together, in the order you've specified, rather than sprinkled throughout the resource.

Phrase searching may produce few results or entirely irrelevant results if:

  • The phrase is too long
  • Words are misspelled
  • The phrase isn't commonly used in your topic or subject area

Key takeaways

Boolean operators can be a great search technique for getting the results you're looking for, but some search engines and databases may use them in slightly different ways. Some may require the Boolean operators to be in all capital letters, and others may insert them automatically into your searches.

OR will give you more results

AND will give you fewer results

NOT will exclude certain words from your results.