Skip to Main Content

Research 101: The Health Sciences

Breakdown the research process and terminology and familiarize yourself with available resources, services, and tools to aid in health sciences research.

What is Boolean Logic?

Boolean Logic centers around (3) words, known as "operators" (AND, OR, & NOT), that are used between search terms to combine concepts in a more precise way.

Boolean Operator: AND

  • Retrieved citations must contain ALL terms​
  • The more concepts/terms joined, the smaller the “intersection” of retrieved citations 

Venn Diagram shows AND retrieving terms "hip" AND "fracture"Venn Diagram shows AND retrieving terms "hip" AND "fracture" AND "elderly"

 

Boolean Operator: OR

  • Retrieved citations may contain one or more of the terms; OR is all inclusive, not exclusive​
  • Don't think of it as retrieving what is in one set or the other, but not both. When combining with OR, results may contain all terms. ​
  • The more terms joined, the larger the “intersection” of retrieved citations​

Venn Diagram shows OR retrieving terms "boy" OR "girl" OR "child"

Boolean Operator: NOT

  • The NOT operator also narrows a search by removing all records that contain a particular word or phrase. ​

    • Example: anorexia NOT bulimia ​

  • The NOT operator is used sparingly; it often screens out useful records

Venn Diagram shows NOT retrieving for term "anorexia" NOT "bulimia"

The Tricky NOT Operator

Our library colleagues, Melinda Davies and Basia Delawska-Elliott, did a fabulous presentation on their visualization for using the NOT-NOT in searches and how it impacts retrieval. Check out the link below to view the full presentation and/or materials on the Open Science Framework.