boolean logic: how to talk to search engines in their own language

Booleanand what it can do for you!

George Boole•He is a rock star

•He did math like Michael did

“Thriller”

•He invented Boolean Logic

This is

BOOLEAN LOGICis a system that combines terms using AND

and OR.

Boolean lets you tell a search engine what you want to know!

How you think How a search engine thinks

George Boole, a famous

mathematician, was also a great animal lover. Do you think he had

any pets?

If the search engine were a person, this would be an

easy problem – it just speaks a

different language!

How a search engine thinks

Boolean is how you translate between your English and the search engine’s super-logical computer language!

Luckily, you only need to know two easy words.

ANDProduces only results that include all

keywords and conditions.

EVERYTHING ABOUT CATS

THIS is everything on the entire Internet that includes the word

CATS.

EVERYTHING ABOUT BOOLE

THIS is everything on the entire Internet that mentions the word BOOLE.

EVERYTHING ABOUT CATS

EVERYTHING ABOUT BOOLE

Here they are together. Everything CATS and everything BOOLE.

Notice the rather sizeable overlap.Sometimes CATS and BOOLE occur together.

HMMMMM.

ONLYstuff about

CATS

AND

BOOLE

EVERYTHING ABOUT CATS

EVERYTHING ABOUT BOOLE

We know that information about Boole’s pet cats must include both the

word “Boole” and the word “cats.”

Therefore, the information we want must be located somewhere in that

overlap!

ONLYstuff about

CATS

AND

BOOLE

By using AND, we have told the search engine to eliminate any results that do

not include BOTH keywords.

Now we have a good chance of finding the information we want!

ORProduces results that include every

keyword and condition.

EVERYTHING ABOUT CATS

Here we have everything about CATS again.

EVERYTHING ABOUT DOGS

And what do you know– here’s

everything about DOGS!

EVERYTHING ABOUT CATS

EVERYTHING ABOUT DOGS

Here they are together.

We don’t want to eliminate either one of these words. We want to know about all the cats as

well as all the dogs.HMMMMM!

EVERYTHING ABOUT CATS

EVERYTHING ABOUT DOGS

When we ask for CATS OR DOGS, the search engine knows that we want every

result that includes EITHER or BOTH keywords.

Now our results include not only CATS, but also DOGS!

COMBO!

EVERYTHING ABOUT CATS

Here we have – again! – everything about CATS.

EVERYTHING ABOUT CATS

EVERYTHING ABOUT DOGS

And now, everything about CATS as well as everything about DOGS.

EVERYTHING ABOUT CATS

EVERYTHING ABOUT DOGS

We know that by using OR, we can include everything about all the

keywords.

EVERYTHING ABOUT CATS

EVERYTHING ABOUT DOGS

EVERYTHING ABOUT BOOLE

What we’re looking for now is information on George Boole’s cats and

dogs – in other words, BOOLE AND anything about his CATS OR his DOGS.

EVERYTHING ABOUT CATS

EVERYTHING ABOUT DOGS

EVERYTHING ABOUT BOOLE

That information will be in the overlap, just like before!

Except now, we’re using TWO operators – AND and OR!

This is how we can tell the search engine to give us only results that include the word “BOOLE” at the same time as either the word “CATS” or the

word “DOGS.”

Now we’re SURE to find what we’re looking for!

BOOLE AND (CATS OR DOGS)

Where is Boolean used?

• Google!– Google already puts AND between all of your search

terms, but sometimes you may want to use OR instead

– Using OR can supercharge your Goo-fu!– Try the example!

• Boole (cats OR dogs)

• Any database– Databases usually give you drop-down AND/OR menus– Even easier than the Goo– Access them for free through your public library,

school or college

Boxford’s Databases

Remember, you’ll need your card to log in!

Academic One-File Lots of good stuff in one neat placeGale Virtual Reference Library Good for quick answersEBSCOhost A bunch of databases, all usefulHeritageQuest Great for looking up your ancestors

http://boxfordlibrary.org/index.php/databases

CONGRATULATIONS!

Now go out and find that stuff!