Q. How do Boolean operators work?

Tips for using Boolean operators and other advanced search techniques

Complex search strategies can seem overwhelming, but they really don't have to be. You can construct effective searches for your topic with just a few simple building blocks.

• Boolean operators — AND, OR, NOT
• Phrase searching — " "
• Nesting — ( )

Phrase searching

Limiting your search to a specific string of words can be an effective way to focus your results. Use double quotation marks to encapsulate specific phrases you would like to appear in your results.

• A search for "free market capitalism" returns only articles that have those three words together in exactly that order (600 results in the library search engine)
• Without the quotation marks, the same search would return any articles that contained these three words, whether or not they're side-by-side (16,130 results in the library search engine!)

Boolean operators

Using AND, OR, NOT to combine or exclude keywords in a search help make your search more effective. Google Scholar, Discovery (the library search), and most databases support the use of Boolean operators.

Key tip: place the operator in ALL CAPS so the search engine recognizes their function.

	Use OR to combine synonyms, variants, or similar concepts. This operator retrieves literature that contains any of these terms OR broadens your search results
	Use AND to combine separate concepts that you would like to appear in a single source This operator retrieves only literature containing both search terms AND narrows your search results
	Use NOT to exclude unwanted concepts This operator retrieves only literature that contains the first term but not the second term NOT narrows your search results

A few additional tips about NOT:

• NOT can be helpful if you're finding a lot of material that's in the general area you're interested in but dealing with a specific subarea you don't want to focus on.
• However, use NOT with caution! You can easily exclude useful articles this way.
• "NOT" doesn't work in Google Scholar. However, you can use a minus sign (-) to accomplish the same thing -- e.g., "participatory research" -children

Nesting

Nesting refers to the use of parentheses to identify elements that must be searched as one unit within a search. Nesting is normally used with the Boolean operator OR to group synonyms for terms or different ways of describing a concept.

Do you remember order of operations from math class? Nesting is the same concept. To see it in action, compare the following two searches:

Correct: "participatory research" AND (children OR "young people")

Parentheses used to group words that refer to the same concept. Retrieve articles that contain the phrase "participatory research" and EITHER of the two phrases in parentheses.

Incorrect: "participatory research" AND children OR "young people"

Without order of operations dictated by nesting, the AND operation happens first. Retrieves articles that contain the terms "participatory research" and children, plus ANY article containing the term "young people"