Skip to Main Content


Well-Built Clinical Questions

Clinical questions can be divided into two types:

"Background" questions

  • As for general knowledge about a condition, test, or treatment
  • Have two essential components:
    • A question root (who, what, where, when, how, why) and a verb
    • A disorder, test, treatement, or other aspect of healthcare

"Foreground" questions

  • Ask for specific knowledge to inform clinical decisions or actions
  • Have 4 essential components (generally stated in PICO format)

Straus, S. E., Glasziou, P., Richardson, W. S., & Haynes, R. B. (2011). Evidence-based medicine: How to practice and teach it. (4th ed.) (p.15). Edinburgh: Churchill Livingstone/Elsevier.

PICO Format

PICO (or PICOT*) format is a way to formulate an answerable clinical question. 

The components of this type of question are:

Patient population/disease

The patient population or disease of interest, for example:

  • Age
  • Gender
  • Ethnicity
  • With certain disorder (e.g. hepatitis)

Intervention or issue of interest

The intervention or range of interventions of interest, for example:

  • Therapy
  • Exposure to disease
  • Prognostic factor A
  • Risk behavior (e.g., smoking)

Comparison intervention or issue of interest

What you want to compare the intervention or issue against, for example:

  • Alternative therapy, placebo, or no intervention/therapy
  • No disease
  • Prognostic factor B
  • Absence of risk factor (e.g., nonsmoking)


Outcome of interest, for example:

  • Outcome expected from therapy (e.g., pressure ulcers)
  • Risk of disease
  • Accuracy of diagnosis
  • Rate of occurrence of adverse outcome (e.g., death)


The time involved to demonstrate an outcome, for example:

  • The time it takes for the intervention to achieve the outcome
  • The time over which populations are observed for the outcome (e.g., quality of life) to occur, given a certain condition (e.g., prostate cancer)

Fineout-Overholt, E., & Stillwell, S. B. (2011). Asking compelling, clinical questions. In B. M. Melnyk & E. Fineout-Overholt (Eds.), Evidence-based practice in nursing & healthcare: A guide to best practice (p. 30). Philadelphia, PA: Wolters Kluwer Health.

Areas in Which Clinical Questions Often Arise

Central issues in clinical work, where clinical questions often arise

  1. Clinical findings: how to properly gather and interpret findings from the history and physical examination.
  2. Etiology/risk: how to identify causes or risk factors for disease (including iatrogenic harms).
  3. Clinical manifestations of disease: knowing how often and when a disease causes its clinical manifestations and how to use this knowledge in classifying our patients’ illnesses.
  4. Differential diagnosis: when considering the possible causes of our patients’ clinical problems, how to select those that are likely, serious, and responsive to treatment.
  5. Diagnostic tests: how to select and interpret diagnostic tests, in order to confirm or exclude a diagnosis, based on considering their precision, accuracy, acceptability, safety, expense, etc.
  6. Prognosis: how to estimate our patient’s likely courses over time and anticipate likely complications of the disorder.
  7. Therapy: how to select treatments to offer our patients, that do more good than harm and that are worth the efforts and costs of using them.
  8. Prevention: how to reduce the chance of disease by identifying and modifying risk factors and how to diagnose disease early by screening.
  9. Experience and meaning: how to empathize with our patients’ situations, appreciate the meaning they find in the experience, and understand how this meaning influences their healing.
  10. Improvement: how to keep up-to-date, improve our clinical and other skills, and run a better, more efficient clinical care system.

Straus, S. E., Glasziou, P., Richardson, W. S., & Haynes, R. B. (2011). Evidence-based medicine: How to practice and teach it. (4th ed.) (p. 18). Edinburgh: Churchill Livingstone/Elsevier.

Templates and Definitions for PICO/PICOT Questions

Question Type



Intervention or therapy

To determine which treatment leads to the best outcome

In (P),
how does (I)
compared with (C)
affect (O)
within (T)?


To determine the greatest risk factors or causes of a condition

Are (P)
who have (I),
compared with those without (C),
at __ risk for (O)
over (T)?

Diagnosis or diagnostic test

To determine which test is more accurate and precise in diagnosing a condition

In (P),
are/is (I)
compared with (C)
more accurate in diagnosing (O)?


Prognosis or prediction

To determine the clinical course over time and likely complications of a condition

In (P),
how does (I)
compared with (C),
influence (O)
over (T)?


To understand the meaning of an experience for a particular individual, group, or community 

How do (P)
with (I)
perceive (O)
during (T)?

Stillwell, S. B., Fineout-Overholt, E., Melnyk, B. M., & Williamson, K. M. (2010). Asking the clinical question: A key step in evidence-based practice. The American Journal of Nursing, 110(3), pp. 58-61. doi: 10.1097/01.NAJ.0000368959.11129.79

Additional Credit

Appreciation to Duke University Medical center Library & Archives, upon whose guide, Evidence-Based Practice (, this page is partially based.

Health Sciences and Engineering Librarian

Profile Photo
Kari Mofford
chat loading...

Claire T. Carney Library
Room 238
285 Old Westport Road
Dartmouth, MA 02747