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boolean searchThe number of websites currently in existence is unimaginable. And while – on a bad day – it only takes Google’s thousands of servers half a second to query approximately 50 billion indexed pages, it takes you significantly longer to scan only the first page of search results. On top of that, you are likely to digress and open irrelevant sites. Why don’t you do your constantly distracted and easily overwhelmed brain a huge favor and learn how to properly construct a search 6 Ways To Reduce Irrelevant Results On Google Search 6 Ways To Reduce Irrelevant Results On Google Search Read More ?

Boolean search logic illustrated in Venn diagrams can help you visualize what you are searching for. If you think this sounds suspiciously like mathematics, you’re spot on. But don’t let that discourage you! It’s pure and simple logic, demonstrated with pretty and very simple diagrams, and so it’s easy. I promise! And I have fun examples to prove it.

The only case in which you won’t need any search logic, is when you search for only a single word, like Earth.

boolean search

What Is Boolean (Search) Logic?

In a search query, Boolean logic helps us define the logical relationship between multiple search terms. The operators used to express the relationship are AND, OR, and NOT. Any number of boolean search terms can be connected with these operators to refine your search results. Let’s look at each operator separately.

OR

  • search results will contain either one or several or all of the search terms
  • best used when you want to pull together results on similar topics

Example: Wind OR Fire

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boolean search engine

The Venn diagram above reveals that a search for Wind OR Fire will show results for Wind, Wind AND Fire (overlapping areas), and Fire.

Example: Earth OR Wind OR Fire

boolean search engine

Likewise, this diagram demonstrates that all boolean search terms by themselves, as well as overlapping content will be shown when connecting the terms with OR. And here is a chance to earn a Like including 5 bonus points if you can tell me who those folks in the center are.

Here are the numbers for Google’s search results for the three search terms and the OR combinations shown above:

  • Earth: 1,280,000,000 results
  • Wind: 909,000,000 results
  • Fire: 2,090,000,000 results
  • Wind OR Fire: 2,980,000,000 results
  • Earth OR Wind OR Fire: 4,210,000,000

As you see, in the case of a Google search, the whole is not greater than the sum of its parts; it’s actually smaller. But since there is redundancy, i.e. overlapping areas, as can be seen nicely in the Venn diagrams above, that makes sense.

Instead of OR you can also use the vertical bar | character when performing a Google search.

NOT or rather –

  • exclude keywords from your search
  • best used when your search is ambiguous

Caution: While NOT is a valid term in Boolean logic, Google doesn’t appear to operate with this term. Instead of NOT, you should use the character. Note that there is no space between the dash and the keyword you want to exclude.

Example: Wind NOT Fire or Wind -Fire

boolean search

The Venn diagram above depicts the results in theory. Below are the actual numbers:

  • Wind: 909,000,000 results
  • Fire: 2,090,000,000 results
  • Wind NOT Fire: 377,000,000 results
  • Wind -Fire: 1,810,000,000
  • and just for fun… Fire -Wind: 5,010,000,000 results

The numbers will vary, depending on which Google domain you are using (my browser defaults to Google.ca) and obviously they also change over time. However, the results above are nothing short of confusing. Let’s say that Google doesn’t necessarily give us all the results, so those numbers are not a reliable source of information. Looking at the first page of results, however, can give you an idea of whether or not your search worked.

boolean search method

Actually trying to understand the results quickly reveals that Google tends to think for you, rather than with you. For the majority of users that’s good because they don’t know what they are doing. Google appears to serve results based on its “experience” rather than the search terms and operators used in the query. This actually is a little disturbing, but good to be aware of. So let’s continue with the theory…

AND

  • search results will contain all search terms
  • results where one of the terms is missing will be excluded
  • best used when you want to retrieve only those results where the search terms overlap

Example: Earth AND Wind AND Fire

boolean search method

Once more, the numbers:

  • Earth: 1,280,000,000 results
  • Wind: 909,000,000 results
  • Fire: 2,090,000,000 results
  • Earth AND Wind AND Fire: 80,500,000
  • and just for fun… Earth Wind Fire: 86,800,000

At least Google cooperates with this boolean search operator. Mind you that AND typically is the default operator in search engines. So whenever you type in more than one keyword, the search engine will automatically connect them with the AND operator. Hence Earth Wind Fire in theory will yield the same search results as Earth AND Wind AND Fire.

Processing & Nesting

You can connect multiple search terms with different operators. But since Boolean logic operates based on mathematical principles, the order in which you connect your keywords will have an effect on your results. To influence your results, it helps to understand how the terms are processed. Per default, keywords are processed from left to right.

Example: Earth AND Wind OR Fire

boolean search method

If you want to change the order in which your keywords are processed, you can of course literally change the order. You can also enclose a set of search terms and operators in parentheses, i.e. nest them. Processing will still be left to right, but the nested elements will be treated as one unit.

Example: Earth AND (Wind OR Fire)

boolean search

This result looks quite different, doesn’t it?

Conclusion

It’s generally good to know how Boolean search logic works when you are working with search engines, at least if they strictly adhere to those operators. Apparently, Google does not, meaning a simple search will often get you exactly what you need, without having to think about it. If you do want to be sure that Google does what you want it to do however, use Google’s Advanced Search. The field all these words corresponds to the AND operator, any of these words equals OR, and none of these words works like NOT. Now you should be able to narrow down your searches a lot better – in theory.

If you desire to become a real power user, I recommend reviewing our article on how to master Google search operators Master the Google Operands: Search Really Fast Master the Google Operands: Search Really Fast Read More , or how to reduce irrelevant results 6 Ways To Reduce Irrelevant Results On Google Search 6 Ways To Reduce Irrelevant Results On Google Search Read More , or which tricks to use when you don’t know what to search for 3 Google Tricks When You Don't Know What to Search For 3 Google Tricks When You Don't Know What to Search For Read More  , or simply review Google’s list of search operators.

Have you ever had trouble getting Google or another search engine find what you were looking for?

  1. Blacke
    October 3, 2016 at 8:17 am

    So much said about Google's using search operators with the keywords but I still suspect that Google themselves have not made it consistent for users of producing the relevant results despite using the operators.
    Take for example if you're searching for images, you could use the image search. The IMAGE search. Not VIDEO search.
    E.g: Images of earth wind and fire music band
    The possible keywords used from Google's Image Search: Earth wind fire music band 1980's
    What you can possibly get would also be results from youtube, other video sites or documents such as from Wikipedia with content from their music videos, live performances, biography or such.
    The results produced instead come out from video sites or documents too which makes your search inaccurate to your needs. So, where is that strict rule code that only images from web sources are produced instead of including sites from video thumbnails or documents from like Scribd and such? Isn't it simple that if you do a video search, thumbnail images are produced only there and does not overlap into the Image Search instead? Wouldn't that help make video or documentary sites adhere to the search codes too without abusing their commercial privileges with keywords for their users? I mean, COME ON!! Let's have an organized standard system in the internet here to control from the cluttering of information.
    Right now, it's messed up.

    • Tina Sieber
      October 3, 2016 at 9:54 am

      Yes, unfortunately search results depend on a lot more than the indexed keywords or categories, hence they can be unpredictable. And I agree, it would be great to have a standard system.

  2. Idun Gundersen
    August 16, 2016 at 8:13 am

    What a great way to explane boolean search. Could I use your illustrations in my teaching? I will credit you off course.

    • Tina Sieber
      August 16, 2016 at 10:17 am

      Thank you for your feedback, Idun! You're more than welcome to use the illustrations if you credit MakeUseOf. Do post a link back here in case this goes online. Thank you!

  3. Nala D.
    June 11, 2015 at 12:35 pm

    I try use Boolean operators for specific results as well. Btw, you made a really interesting visually-appealing explanation!

    • Tina Sieber
      June 12, 2015 at 2:45 am

      Thank you for the feedback, Nala and glad you enjoyed the article! Feel free to share it. :)

  4. David
    April 5, 2015 at 1:04 am

    But you can't do the + and "all words in the quotes in that order" thing anymore!!!

    Woe is me!!!

  5. Josh M
    July 14, 2013 at 6:02 am

    Great way of explaining! Thank You

  6. Joel Wavrecan
    May 21, 2013 at 12:50 pm

    Earth, Wind, and Fire. An American band that has spanned the musical genres of soul, disco, R&B, funk, jazz and rock. (ref.Google)

  7. Stephanie Staker
    May 21, 2013 at 5:28 am

    Gotta tell you that you lost me. Remember now that I am a senior citizen pushing 70 and I have NEVER figured out boolean logic. After the first few sentences of this article, I started falling asleep and, Tina, that is not your fault. It is mine. I have consistently had problems finding what I am looking for in the "real world" as well as online. My belief is that you have to know how the person who "assigned" the place where your/my info is located, thinks. Stay with me here: many years ago, I was taking classes to become a certified paralegal. One of the classes was on doing research which is really important to know in order to get a job in this field. I had one heck of a time. My logic is not the annotated statute logic so it was a constant battle for me to find the info I needed. Fortunately, in today's digital world, all of this legal stuff is on DVD along with various search engines that "speak" to all of us. What I mean is that there are search engines out there who think like I do so "we" (the search engine and I) are able to find what I am looking for. Back to this issue of the boolean search stuff, I find that doing a search in Google (my favorite search engine) is pretty handy and sometimes scary. It generally reads my mind after I type the first few letters of my search query. The page appears magically and more often than not, what I want to know is the first thing on the list. :)

  8. null
    May 20, 2013 at 7:13 pm

    I used to use Boolean operators all the time. It made for very specific search results. I still use them once in a while but now it seems most search engines just seem to ignore them. Too bad. Making it easier seems to have made it less useful.

  9. Eweforia
    May 19, 2013 at 10:16 pm

    Well, I'm probably old enough to know Earth, Wind, & Fire, but I wasn't paying attention when I was young. So I copied the photo, saved it to harddrive, and Googled to find similar photos. (That's the power of Google, which was what the article was about!) Presto, 401 similar photos, helping me deduce that the group's name was Earth, Wind, & Fire.

    • Tina Sieber
      May 20, 2013 at 6:53 am

      Amazing what Google can do with similar image search, isn't it? Only a few years ago that was science fiction to most of us.

  10. KRS
    May 19, 2013 at 9:42 pm

    I think PROXIMITY SEARCH is the most important search engine feature after word or string finding -- that is, limiting results to hits in which one term or string appears within X number of words from the other. As a lawyer,I use Lexis/Nexis and WestLaw proximity operators constantly, along with the invaluable KWIC (Key Word In Context) view, to eliminate innumerable false hits where the two words (or strings) are scattered.

    Google has the NEAR operator, and Exaled has a more useful version, but I'd switch in a heartbeat to a search engine with Lexis/Nexis or WestLaw proximity operators and KWIC. In fact, if Nexis wasn't so expensive, it would be my default search engine.

    • Tina Sieber
      May 20, 2013 at 6:54 am

      Thank you for the insight! The NEAR operator is a good one to remember.

  11. Chip Stewart
    May 19, 2013 at 6:41 pm

    The folks in the middle are Earth, Wind & Fire, a band from, like, the late 60s, man. They are some of the coolest, hippest musicians around!

  12. isse
    May 19, 2013 at 2:46 pm

    "Google tends to think for you, rather than with you ... This actually is a little disturbing"

    Over time, I've become too disturbed by Google to use them any longer. Does this advice apply apply similarly to Bing?

    I already use quotes and the minus sign, but I'd never heard of using the vertical bar, parenthesis or that keyword order changed the processing..

    • Tina Sieber
      May 20, 2013 at 6:55 am

      I didn't try Bing. However, if you use the examples above and compare the numbers, you should be able to figure out how strictly Bing adheres to operators or how much the search results are controlled by custom algorithms.

  13. Vincent Paul Migliore
    May 19, 2013 at 1:27 pm

    The people in the center are the singing group, "Earth, Wind and Fire" !! Cool, huh? (Which true of WIND (maybe), but not EARTH -OR- FIRE.

  14. Russ
    May 19, 2013 at 10:53 am

    Great article that is clear and easy to understand.

    • Tina Sieber
      May 20, 2013 at 6:56 am

      Glad to hear that, Russ. :)

  15. Rochelle
    May 19, 2013 at 1:13 am

    The people are Earth, Wind and Fire, a rock group.

  16. Cynthia Nevin
    May 18, 2013 at 2:36 am

    The group is Earth, Wind and Fire!

  17. dr anwar yarkhan
    May 18, 2013 at 1:20 am

    Excellent writeup. Thanks.
    Request one go PDF file instead of giving so many reference links. And without frills please. Great topic greater insight.

    • Tina Sieber
      May 20, 2013 at 6:57 am

      I'm not sure I understand your suggestion. Would you like to have a PDF of the article or a PDF with references or a PDF with both?

      • dr anwar yarkhan
        May 20, 2013 at 9:04 am

        Search Engines. There are several writeups explaining how to use se. Like: how to master Google search operators; how to reduce irrelevant results; tricks to use when you don't know what to search for; and others to educate to deal with se., may kindly be given in single writeup in PDF format. Thanks.

        • Tina Sieber
          May 20, 2013 at 11:00 am

          Ah, you're asking for a PDF manual on the subject. We do have a search manual already, but it doesn't go into the theory that much.

  18. Ben
    May 18, 2013 at 12:34 am

    In the diagram, the fourth picture down, the picture in the center is a depiction of all three - Earth, Wind, and Fire.

  19. Ali Khan
    May 17, 2013 at 9:11 pm

    A great info to share .... interesting :))

  20. null
    May 17, 2013 at 8:38 pm

    This posting helped me find a song. Thank you Tina.

    • Tina Sieber
      May 20, 2013 at 6:57 am

      Very welcome!

  21. Ralph John Soden
    May 17, 2013 at 8:23 pm

    Love it! Nice way to show logic meaning.

  22. Mark Soderlund
    May 17, 2013 at 7:09 pm

    Dear null - It isn't mathematics - it's Logic.

    Earth Wind and Fire - good band - excellent stage show - especially if you catch them on the 21st of September.

  23. Brian
    May 17, 2013 at 7:08 pm

    The folks in the middle...are the singing group: Earth, Wind, and Fire (I had their hit "September" going through my mind when I first saw your post).

  24. Monali Parmar
    May 17, 2013 at 5:21 pm

    I use Boolean logic every single day at work! I am a Sourcing Analyst in the Recruiting world and most of us use this to find qualified candidates by zeroing in on certain keywords. I will also use this in my personal life if I need to narrow down my Google results while shopping or just doing research. Thanks for sharing this!

  25. Guy McDowell
    May 17, 2013 at 5:15 pm

    It's the Jackson 5 with 4 cousins.

    I just don't find that Google responds as strictly to Boolean operators as it once did. I barely even bother with them anymore. Which is sad.

    • Tina Sieber
      May 17, 2013 at 8:26 pm

      Yeah, that's what I found. I guess Google developed their algorithm to adapt to people's logic rather than to teach people how to properly use search operators.

  26. null
    May 17, 2013 at 5:14 pm

    I am always trying new ways to get better search results. This will help

  27. Greg Moyer
    May 17, 2013 at 4:24 pm

    Earth wind and fire

  28. Steve Fahnestalk
    May 17, 2013 at 3:56 pm

    Well, duh--it's the group Earth, Wind and Fire. A great group for its day.

    • Your Mom
      May 17, 2013 at 5:18 pm

      You're an ass

      • Steve Fahnestalk
        May 17, 2013 at 5:23 pm

        *I'm* an ass? You're the dipsh*t casually insulting people you don't know for no reason.
        Or, as Captain Kirk said, "Double dumbass on you!"

        • Your Mom
          May 17, 2013 at 5:29 pm

          ha ha - quoting Captain Kirk - your mom was right.
          the 'well, duh' comment was lame and insulting to a girl that did a pretty good job in her post. You got the 5 points, but sorry you lost 3 for being a tool.

        • Steve Fahnestalk
          May 17, 2013 at 6:17 pm

          "Duh," is well-known as shorthand for "That's an obvious question," and is only seen as insulting by idiots. Which you obviously are.
          If the person who wrote the article has a problem--and she's probably a woman, not a girl, you sexist pig--then she can take it up with me herself.
          You, on the other hand, are too young and stupid to waste any more time on. I'm done with you. Post away, dumbass!

    • Mrs. Steve
      May 17, 2013 at 7:01 pm

      Stop responding to your mom that way - she's only trying to provoke you

      • Steve Fahnestalk
        May 17, 2013 at 7:05 pm

        You're right. But she's hardly old enough to be *my* mom, who--by the way--had a degree and knew the difference between "who" and "that" as well as "girl" and "woman."

        But, you know, I'd hate to see the species die out entirely--if we don't feed the trolls, who will we laugh at when they die of hunger?

        • Mrs. Steve
          May 17, 2013 at 7:14 pm

          That's the way these Obama lovers are. Always critical of the rest of us. That person probably has no job and has the government paying for her high-speed internet, how else is she casually responding to posts during the workday?

    • Lavender
      May 20, 2013 at 4:37 pm

      (The *Gasp!* comment was for Jason Heiken. Apparently some old folks can't hit the correct reply button).

  29. null
    May 17, 2013 at 3:43 pm

    LOL! But good info....Shared.

  30. Anup Agarwal
    May 17, 2013 at 3:41 pm

    The bunch in the middle are funky American band. The members are Maurice White, Philip Bailey, Al McKay, Verdine White, Larry Dunn, Ronnie Laws, Sonny Emory, Ralph Johnson, Don Myrick, Kim Johnson, Roland Bautista, Wade Flemons, Jessica Cleaves, Daniel de los Reyes, Andrew Woolfolk, Philip Bailey Jr, Gary Bias, Myron Mckinley, Bobby Burns Jr., B. David Whitworth, Raymond Lee Brown, Greg "G-Mo" Moore, Morris O' Connor, Sheldon Reynolds, John Paris, Fred White, Reggie Young

    • Lavender
      May 20, 2013 at 4:32 pm

      *Gasp!* And yet you're on a computer? And using the Internet?! Shades of Jethro Gibbs! Who knew people over 35 could walk and chew gum, let alone use a computer! (Besides me, that is. Since I've been on the Internet since 1994. And yep, I'M that old, too!)

  31. Jason Heiken
    May 17, 2013 at 3:11 pm

    It's Earth Wind and Fire. And, I didn't even need to look it up. (yup....I'm that old...)

  32. Scott M
    May 17, 2013 at 12:08 pm

    I have been doing it this this for a while now after being tipped by a friend.I hat to say it about a monolith but they have a search engine that rises far above all of the others,excepting specific tech search engines.

  33. Dee Martin
    May 17, 2013 at 10:29 am

    Loved this - I will share - great way to teach kids how to narrow search results! (And I love Earth, Wind and Fire - Keep Your Head to the Sky!

  34. Bert Teuling
    May 17, 2013 at 9:00 am

    The Bunch in the middle are Earth Wind and Fire A wonderful fusion funk group that were before their time:)

    • Keith S
      May 18, 2013 at 7:02 am

      And let us NOT leave out... I CAN'T REMEMBER THEIR NAME! Oh, well, It is late & I am sleepy! Later bro & YES: Earth Wind and Fire were before their time:) :)

      • Lavender
        May 20, 2013 at 4:35 pm

        No, they weren't. They were of their time. Just because their music is better than what's called music now, doesn't mean they were before their time.

  35. null
    May 17, 2013 at 4:10 am

    Oh no, it's mathematics.

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