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NURS 7301 - Methods for Evidence Based Practice: Search the Lit

Boolean Operators

This is a form of algebra where variables are truth values, rather than numbers. It was named after, and invented by, George Boole, an English mathematician in the 17th century. It combines concepts by conjunction (AND), disjunction (OR), or negation (NOT).

Boolean operators as Venn diagrams

You will use Boolean operators to combine search terms in meaningful ways. Terms in one concept will combine with OR. Combine with AND across concepts.

Example: hand sanitiz* OR handwashing OR hand w/5 scrubbing

  • All of these terms are part of the concept that has to do with cleaning the hands. Combining with OR widens the pool of results.

Example: (hand sanitiz* OR handwashing OR hand w/5 scrubbing) AND (cross infection OR "hospital acquired infection")

  • This combines two concepts (cleaning the hands and getting an infection) and will limit the results.

All databases use Boolean operators in the same way.

Deciding Where to Search

PILOTS Database

The Published International Literature on Traumatic Stress (PILOTS) Database is an electronic index to the worldwide literature on PTSD and other mental health consequences of exposure to traumatic events. Unlike other databases, the PILOTS Database does not restrict its coverage to articles appearing in selected journals. It attempts to include all publications relevant to PTSD and other forms of traumatic stress, whatever their origin without disciplinary, linguistic, or geographic limitations.

The Pieces

Steps in the literature search proces:

  1. Identify your minimum searchable concepts using the research question format
  2. Build groups of small searches in your database(s) of choice using each searchable concept
  3. Combine the groups using Boolean operators to produce results
  4. Refine your search based on returned citations - be sure to check the keywords and subject headings!

Searching the Literature

Tips for searching the literature