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University Library, University of Illinois at Urbana-Champaign

Evidence-Based Medicine (EBM)

ASK the Question

Most clinical encounters lead to a need for information. The first step in EBM is to translate the need for information into a question that can be answered by clinical research. 

There are "foreground" questions and "background" questions.

Background questions - find answers in medical textbooks and/or clinical tools that provide topic overviews of diseases and conditions

  • look for general knowledge  
  • contain a who, what, where, when, or why 
  • look at an overview of a health care issue

Foreground or Clinical questions - find answers in clinical tools or databases

  • look for specific information to make clinical decisions
  • sometimes called "PICO" questions
  • focus is on diagnosis, therapy, prognosis, harm, prevention, etiology

PICO Question Framework for Clinical Questions


  • Who is the patient?
  • What clinical terms describe the patient?
  • What clinical terms describe the problem the patient is experiencing?


  • What steps are you considering?
  • What options do you have?
  • How specific can you be about your plan?


  • Are there alternatives to what you are considering?
  • Is there comparative research on treatment options?
  • What would you do if you did not take the steps you plan to?


  • What result or outcome is most important to your patient?
  • What result or outcome do you think is realistic?
  • What outcomes are reported in the literature for different treatment options?

Sometimes you will see a "T" added to the question. T can represent:

Type of question being asked (therapy, diagnosis, etiology, harm, prognosis, prevention)

Type of study that will best answer the question (RCT, Cohort Study, Systematic Review)

Time to outcome - within a month, year, etc.

TYPES OF QUESTIONS & TYPES of STUDIES to Answer the Question

Therapy - effectiveness, efficacious, cost/benefit, risk/harm  >>>RCT, Clinical Trial

Diagnosis - which test is more accurate, affordable, safe? specificity vs. sensitivity, likelihood ratios. Often measure against a gold standard test
>>> Prospective, blind controlled trial

Prognosis - likely clinical course over time, including anticipated complications  >>> Cohort Study, Case Control, Case Series, Case Report

Etiology/Harm - cause or increased liklihood  >>>RCT, Cohort Study, Case Control

Prevention - reduction in risk or chance of disease; interventions that modify risk factors  >>>RCT, Cohort Study, Case Control

Qualitative - attitudes and beliefs; impact on quality of life  >>> Observational Studies