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Evidence-Based Practice

Resources to support your evidence-based practice.

Getting Started

PICO

  • Patients or Population: Who are the relevant patients?

  • Intervention(s) or Exposure(s): For example, diagnostic tests, foods, drugs, surgical procedures, time, or risk factors. What are the management strategies we are interested in comparing or the potentially harmful exposures about which we are concerned?

  • Comparator: For issues of therapy, prevention, or harm, there will always be both an experimental intervention or putative harmful exposure and a control, alternative, or comparison intervention or state to which it is compared.

  • Outcome: What are the patient-relevant consequences of the exposures in which we are interested? We may also be interested in the consequences to society, including cost or resource use. It may also be important to specify the period of interest.

Adapted from Users' Guide to the Medical Literature

Question Types and Study Design

Question Type Description Best Types of Evidence
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 Randomized Controlled Trial (RCT)
Diagnostic tests how to select and interpret diagnostic tests, in order to confirm or exclude a diagnosis, based on considering their precision, accuracy, acceptability, expense, safety, etc Prospective, blind comparison to gold / reference standard
Prognosis how to estimate a patient's likely clinical course over time due to factors other than interventions Cohort Study > Case Control Study > Case Series
Harm/Etiology how to identify causes for disease (including its iatrogenic forms) Cohort Study > Case Control Study > Case Series
Prevention how to reduce the chance of disease by identifying and modifying risk factors and how to diagnose disease early by screening RCT > Cohort Study > Case Control Study > Case Series

Adapted from Duke University Medical Center Library and Archives