Search Strategies to Improve Your Research

The video below was created by McMaster University Libraries and demonstrates with graphics how Boolean Operators work. Check it out!

There are three commonly used Boolean Operators: AND, NOT, and OR. These operators can help you narrow or broaden your search.

Using the AND operator

Using the AND operator narrows your search by showing you only the results that include all of your search terms. For example, look how my search results in Olin Scholar changed when I utilized the AND operator:

• Engineering = 28,733,257 results
• Engineering AND Environmental Impacts = 201,100 results
• Engineering AND Environmental Impacts AND Climate Crisis = 463 results

Using the AND operator is a great way to focus in on your topic. You can use as many search terms and Boolean operators as you would like in one search query.

Using the NOT operator

Using the NOT operator narrows your search by showing you results that do not include a particular search term. This can be helpful if you are getting results on topics that you are not interested in. Below are a few examples of how the search results in Olin Scholar changed when using the NOT operator:

• Infrastructure = 1,795,891 results
• Infrastructure NOT Transportation = 1,496,961 results
• Infrastructure NOT Transportation NOT Business = 1,033,527 results

Using the NOT operator is often something you will decide to include after analyzing your original search. Sometimes there are certain definitions of a term that you do not want to include, so the NOT operator can be helpful.

Using the OR operator

Using the OR operator broadens your search by showing you results that include either search term, but not necessarily both search terms. For example, look at how the number of results I got grew as I utilized the OR operator:

• Materials Science = 5,888,680 results
• Materials Science OR Materials Engineering = 9,030,372 results
• Materials Science OR Materials Engineering OR Chemistry = 26,000,999 results

This operator can be useful if you want to include synonyms for a term within your search.

Using multiple operators

You can use multiple operators in one search query as well. When adding additional operators, they follow a similar structure to the Order of Operations. You can use parentheses to help you organize your results. The examples below show how the search results change depending on whether you use parentheses.

• Computer Engineering OR Computer Science AND Job Outlook = 3,237,540 results
• (Computer Engineering OR Computer Science) AND Job Outlook = 149 results

Using parentheses alongside your operators can make sure that you are limiting the results to only the information you want.