Based on the clinical scenario above:
P: bad breath, male, adult
I: tooth-brushing
C: doing nothing
O: reduction in bad breath
Not all of these terms will be used directly in the search, but it's good to be aware of all potential search terms.
Here's the question that you'd base your search on:
Does tooth-brushing, in comparison with doing nothing [i.e., what the patient is currently doing], decrease bad breath in older male adults?
Here are the terms (also known as a "search string") that will be used to search the database:
(bad breath OR halitosis) AND (toothbrushing OR oral hygiene)
Bad breath & halitosis are synonyms for one concept, so they're connected by OR & placed within parentheses.
Toothbrushing & oral hygiene are synonyms for the second concept. They're connected to the first concept with AND.
| Boolean Connector | Purpose |
|---|---|
 |
ANDConnects different concepts (keywords). Narrows down the number of results. |
 |
ORConnects synonyms. Expands the number of results. |
 |
NOTExcludes a concept. Use with extreme caution (even librarians don't use this one much). |
These are some examples of how each type of Boolean operator looks when used with keywords:
It expands the number of results on the topic.
| Examples Topics of Interest | Search terms connected by OR |
|---|---|
| College Students | college OR university OR higher education OR undergraduate OR post secondary |
| Racism | racism OR racial bias OR prejudice OR systemic racism OR racist |
| online courses | online education OR online learning OR online teaching |
| learning communities | community OR engagement OR connection OR presence |
It narrows down the number of results.
| Example Topics of Interest | Search terms connected by AND |
|---|---|
| College students experiences of racism. |
college OR university OR higher education OR undergraduate OR post secondary AND racism OR racial bias OR prejudice OR systemic racism OR racist |
| The role of engagement in successful online courses. |
community OR engagement OR connection OR presence AND online education OR online learning OR online teaching |
Use with extreme caution.
| Example Topic of Interest | Search terms connected by NOT |
|---|---|
| Quitting tobacco, but just smokeless tobacco (eg vaping). | Tobacco cessation NOT smoking |
| Cloning, but excluding sheep. | Cloning NOT sheep |