Research Guides: Evidence-Based Practice: Step 1: ASK

The Well-Built, Patient-Oriented Clinical Question

PICO is a mnemonic used to describe the four elements of a good clinical foreground question. The PICO model is used in Evidence-Based Medicine to assist in formulating a searchable clinical question relating to therapy, diagnosis, prognosis, etiology or harm.

Patient scenario: A middle aged woman presented with exacerbation of her usual pattern of migraine. She asked specifically about whether riboflavin might help as she had heard from a friend that it helped prevent migraine. Together you formulate the question, in patients with frequent migraines, is riboflavin effective in the reduction of migraine frequency or severity?

*Question Components*	*Your Patient Scenario*
P - Patient or Population Describe the most important characteristics of the patient. (e.g., age, disease/condition, sex, ethnicity?)	Patients with migraine
I - Intervention; Prognostic Factor; Exposure Describe the main intervention. (e.g., drug or other treatment, diagnostic screening test)	riboflavin
C - Comparison (if appropriate) Describe the main alternative being considered. (e.g., placebo, standard therapy, no treatment, the gold standard)
O - Outcome Describe what you're trying to accomplish, measure, improve, affect. (e.g., reduced mortality or morbidity, reduced length of stay, improved memory, accurate and timely diagnosis. You may wish to add time factors.)	Reduced frequency and/or severity of migraine

Since this is a question about a therapeutic intervention, a randomized controlled trial would be ideal to provide an answer.

See this link for a full description of the approach taken to answer this question. More practice questions are available in the Evidence Based Medicine Toolbox developed by the McMaster Knowledge Translation Program. https://ebm-tools.knowledgetranslation.net/resource

Publication Types Evidence Pyramid

Ideal Study for Type of Question

Depending on the clinical question, different types of research study will provide the best evidence. Triple-blind designed RCTs are the gold standard for therapy and diagnosis, but cohort or case-control studies will better answer etiology or harm questions.

Type of Question	Ideal Type of Study
Therapy	RCT
Prevention	RCT > Cohort Study > Case Control
Diagnosis	Prospective, blind controlled trial comparison to gold standard
Prognosis	Cohort Study > Case Control > Case Series/ Case Report
Etiology/Harm	RCT > Cohort Study > Case Control
Cost Analysis	economic analysis

Note: Guidelines, meta-analysis, systematic reviews, when available, often provide the best answers to clinical questions.

Accessing/Acquiring the evidence

Once you have developed a searchable clinical question and identified search terms; continue on to Step 2: Accessing/acquiring information.