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Evidence - Based Practice

This guide is a collection of resources for learning Evidence-based Nursing.


The PICO question is a different way to think about the clinical questions that arise during patient care. Unlike informational questions, these questions are quite complex and sometimes a challenge to formulate. They are comprised of specific types of components, or concepts, and have a purpose throughout the EBP process.

The PICO Formula

It is not coincidence that this process is called formulating. When you formulate a PICO question, you are creating a formula that does several things:

  • Focus the question by identifying the components or concepts in the question
  • Defines the concepts that will be used when performing a complex literature search
  • Used to ascertain which articles in a search retrieval best address the question
  • Helps determine if studies found address the components of the original question
  • Ultimately the process will provide the information needed to make a decision whether the intervention in the PICO question should be implemented

According to the Centre for Evidence Based Medicine (CEBM), "one of the fundamental skills required for practicing EBM is the asking of well-built clinical questions. To benefit patients and clinicians, such questions need to be both directly relevant to patients' problems and phrased in ways that direct your search to relevant and precise answers."

A well-built clinical foreground question should have 4 components. The PICO model is a helpful tool that assists you in organizing and focusing your foreground question into a searchable query. Dividing into the PICO elements helps identify search terms/concepts to use in your search of the literature.

P = Patient, Problem, Population (How would you describe a group of patients similar to you? What are the most important characteristics of the patient?)

I = Intervention, Prognostic Factor, Exposure (What main intervention are you considering? What do you want to do with this patient? What is the main alternative being considered?)

C = Comparison (Can be None or placebo.) (What is the main alternative to compare with the intervention? Are you trying to decide between two drugs, a drug and no medication or placebo, or two diagnostic tests?)

O= Outcome (What are you trying to accomplish, measure, improve or affect? Outcomes may be disease-oriented or patient-oriented.)

Locating evidence in literature depends upon asking an effective research question. Use the PICO mnemonic to build that question.


     P -- patient, population, participant
      I -- intervention, therapy
     C -- comparison  (not always required)
     O -- outcome

 4 Types of PICO Questions

     1. Diagnosis
     2. Prognosis
     3. Therapy
     4. Etiology



Diagnosis PICO:
In children with respiratory infection, is the respiratory rate as effective as chest x-ray in detecting pneumonia?

Prognosis PICO:
In premature infants (compared to full-term infants), what is the lifetime prevalence of hearing deficit?

Therapy PICO:
In patients with recurrent infection, do antibiotics, compared to no treatment, reduce recurrence rate?

Etiology PICO:
In post-menopausal women, does hormone replacement therapy increase the risk of breast cancer?


PICO can be a useful tool for asking focused clinical questions.


PICOTT can also be used where T = type of question (eg. therapy) T = type of study (cohort, RCT, etc.)

PICO will help to clarify the question, determine the search concepts and type of study that is most appropriate to answer the question type.

PICO Question Formats:

 Fill in the blanks with information from your clinical scenario:

In_______________, what is the effect of ________________on _______________ compared with _________________?

For ___________ does the use of _________________ reduce the future risk of ____________ compared with ______________?

Are (Is) ________________ more accurate in diagnosing _______________ compared with ____________?

Does ____________ influence ______________ in patients who have _____________?

Are ______________ who have _______________ at ______________ risk for/of ____________ compared with _____________

How do _______________ diagnosed with _______________ perceive __________________?

Melnyk, B. M., & Fineout-Overholt, E. (2011). Evidence-based practice in nursing & healthcare: A guide to best practice. Philadelphia: Wolters Kluwer/Lippincott Williams & Wilkins.