Boolean Operators


Boolean Searching
In this tutorial you’ll learn about the Boolean operators AND, OR and NOT.
We’ll talk about AND first.
Use the Boolean operator AND when you want both terms included in your search results.
AND narrows a search.
For example, let’s say you’re looking for articles about birth control legislation.
The first term we want to search for is “birth control.”
If we search just for “birth control” we’re going to get a lot of articles about birth control but not necessarily about birth control legislation.
We need to include the term legislation so that articles we find are relevant to birth control legislation.
To narrow our search and retrieve articles which include the terms “birth control” and legislation we use the Boolean operator AND.
By using AND we retrieve just what is in the blue oval, articles that contain the terms “birth control” and legislation.
Now let’s talk about OR.
The OR Boolean operator broadens your search.
Use OR to combine synonyms or related words.
For example, “birth control” OR contraception
OR broadens a search.
When we use OR we retrieve everything in both circles.
For maximum search results, combine the operators OR and AND in a single search.
For example, a search in Google looks like this
Note Google automatically adds the AND operator.
Also note the use of parentheses.
These are use to group the OR words together.
Here’s how the search looks in the library catalog
Notice the OR and the AND
Now let’s talk about the Boolean operator NOT.
Use NOT to exclude documents containing a specific word.
Let’s say when we run out search (“birth control” OR contraception) AND legislation
We get a lot of hits having to do with Canada.
But we’re not interested in Canada, so we use the NOT Boolean operator.
Our search string looks like
(“birth control” OR contraception) AND legislation NOT Canada
Note, Google uses the minus sign for NOT.
In review
AND narrows a search. Use it to combine multiple concepts.
OR broadens a search. Use it to search for synonyms and related words.
Use parentheses to group OR words together.
Not is used to exclude articles with a specific word from a search.
The end.


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