Why do searches pictured on the library site use AND or OR between words? Should I do that when I search?
Answer
Those are examples of 'Boolean operators'. Boolean operators are pieces of logic used to refine search parameters to narrow or expand your search results as desired by adding extra requisite information to your search.
Most databases and search engines understand at least three of the main logic operators: AND, OR, NOT
- AND
- Requires the results to contain both or all the terms combined with AND
- Narrows your results - the more ANDs you use, the fewer results you will retrieve. Most databases assume when you type in words together that you want them “anded” together unless you tell it otherwise.
- OR
- Results contain either, both, or any combination of the terms combined with OR
- Expands your results - use OR between synonyms (The columns in the above chart)
- NOT
- Results will not contain ANY articles that used the term(s) indicated after NOT
- Narrows your results – Don’t use this unless you are positive you need to exclude a word or phrase completely. NOT is pretty powerful.
For more information on these and other examples of Boolean operators, please check the Boolean Logic section on this page: PICO - Research - LibGuides at Mercy College of Health Sciences (mchs.edu)