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Evidence-Based Clinical Practice: Search strategy

Boolean operators

Venn diagram demonstrating overlap of search terms with operator "and"

Venn diagram demonstrating expanded overlap of search terms with operator "or"

Venn diagram demonstrating exclusion of search terms with operator "not"

Search terms

1. Using your PICO question, identify the key words - those terms that are most specific to your question.

Example: Among elderly nursing home residents with depression, are therapy animal visits effective in managing or reducing depressive symptoms?

1. elderly nursing home residents 
2. therapy animal visits 
3. Depression

2. Brainstorm synonyms for those words.


Elderly: geriatric, senior citizens, aged
Nursing home residents: assisted living facility, long-term care facility
Therapy animal visits: animal assisted therapy, equine therapy, canine therapy, pet therapy, animal based therapy
Depression: depressive symptoms, emotional depression, major depressive disorder

3. Create a search strategy by using Boolean operators to connect your search terms.

Example: (elderly OR geriatric OR "senior citizen" or aged) AND ("therapy animal" OR "animal assisted therapy") AND depression 

4. Test your search strategy in your chosen database and review your results.

Search modifiers

Diagram showing use of quotation marks, parenthesis, and asterisk as search modifiers

Subject headings

Subject headings or MeSH terms are controlled vocabulary which work like a thesaurus.