The Clinical Question

Study Designs

Evidence Sources

Critical Appraisal

Applying Evidence

Saving Time

EBVM Resources

Constructing the Clinical Question

Topics Covered

Introduction to the clinical question
PICO formula
Which questions to ask
Clinical Example #1
Clinical Example #2

Introduction to the clinical question
Evidence-based medicine begins with a question that arises from a patient interaction. In preparation to search for relevant and useful evidence, a clinician should first construct an answerable, focused question. Good clinical questions have answers that will guide the clinician's decision making. The question should be specific and should focus on outcomes that are important to the patient and/or owner. The elements you choose to include in the question will be the elements you include in your search strategy when you search the literature for evidence.

PICO formula for constructing questions
A formula for developing good clinical questions is known as PICO, which stands for Patient (or Problem), Intervention, Comparison and Outcome. By including these elements, the clinician focuses on the key elements of the problem and the desired outcome.

Patient/problem Include the most important characteristics of the patient and problem. This should include the primary complaint or problem and possibly co-existing conditions or characteristics of the patient that may affect diagnosis (e.g. species, age, sex)
Intervention Includes the main intervention, prognostic factor or exposure being considered (e.g. a drug, a diagnostic test, .)
Comparison Includes the main alternative you are considering. You may be deciding between two tests or between two courses of treatment. A specific comparison is not always included.
Outcome Desired outcome (e.g. elimination of symptoms, accurate diagnosis)

Which questions to ask
A specific patient interaction may generate several possible clinical questions. It is not always possible and certainly not time effective to try to answer all of the questions. When deciding among questions, ask yourself if the answer to the question would change how you handle the patient. You should ask the questions which are (Rosenthal):

  • Most important to the patient's well being
  • Feasible to answer within available time limits
  • Apt to arise with future patients in your practice
  • The most clinically interesting

Clinical Example #1
During a routine exam, Mrs. Smith reports embarrassedly that her two year old beagle has been eating its own feces. She asks your advice on how to treat this behavioral problem. You have read about and have recommended using a citronella spray collar in the past. However, you recently heard from an enthusiastic colleague that sound therapy is also being used effectively to address this problem.

Using PICO, we can break the scenario down into its key elements:

Dogs that eat their own feces
Sound Therapy
Citronella spray collar
Elimination of the behavior

Clinical Question: In dogs that eat their own feces is sound therapy or a citronella spray collar more effective at eliminating the behavior?

Now You Try!

Read the following clinical scenario, and using the PICO formula construct a focused, answerable clinical question. When you are ready, compare your results to ours. There will be some variation in correct responses.

Clinical Example #2
One of your clients, a local dairy farmer, calls and asks you about treating a postpartum cow with a fever. He wants to know if treating the cow will increase milk yield. Ceftiofur is effective in reducing fever in postpartum cows, but you do not know if it has any effect on milk production.


Clinical Question?



See Answers


    Next: Questions and Study Designs
Return to top of the page