Skip to Main Content

Evidence-Based Clinical Practice: Asking a clinical question & PICO


PICO is a method for extracting the key concepts from a clinical question.

Resources for PICO

Search Modifiers

Quotation Marks

Example of quotation marks

Search results will contain exactly the terms inside the quotation marks. 

Example: "lower back pain"



Example of parenthesis

Used with Boolean operators to group synonyms and related terms together

Example: (adjustment OR manipulation)



Example of asterisk

Retrieves alternate word endings

Example: teach* retrieves: teach, teacher, teaches, teaching



The PICO Strategy

PICO stands for: Patient/Problem, Intervention, Comparison and Outcome. When considering a clinical problem, use PICO to analyze the most important concepts to research.



Patient or Problem: Demographic characteristics of the patient such as age, sex; condition or other factor, such as: congestive heart failure, hypoglycemic, smoker, obese


Intervention: Treatment, prognostic factor, exposure, such as a drug, test, surgery, adjustment


Comparison: Are you trying to decide between two treatments/drugs/procedures, etc.? (optional/placebo/”sham”)


Outcome: What is desired for the patient?


Example: In adult patients with whiplash following a car accident, how effective is chiropractic care compared to exercise in restoring range of motion?


adult, whiplash


chiropractic care




restoring range of motion 

Note: Not all parts of PICO will apply to every clinical question. For example, not every clinical question needs a comparator and sometimes it can be challenging to find research that compares two different interventions in the same article. Instead, you might find implicit comparisons between standard care, placebo, or non-intervention. 

Search strategy

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?

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.

Boolean Operators

AND retrieves results with both terms

Venn diagram showing use of "AND" Boolean operator

Example: chiropractic AND manipulation


OR retrieves results with both or either term

Venn diagram showing use of "OR" Boolean operator

Example: manipulation OR adjustment


NOT retrieves results with only one term and excludes results with the other

Venn diagram showing use of "NOT" Boolean operator

Example: manipulation NOT adjustment