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

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.

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