Evidence Based Health Care

Library of the Health Sciences

Planning the Search

There are several worksheets available directed at planning your search.  Here is one example and a guide for thinking through the PICO process.

Using the PICO Format

P  Patient, Population, or Problem of Interest
I   Intervention, Exposure, Prognostic Factor (treatment, diagnostic test, risk factor, etc.)
C Comparison (implicit or explicit)
Outcome of interest (positive or negative)
Example “In patients with heart failure from dilated cardiomyopathy who are in sinus rhythm …” “… would adding anticoagulation with warfarin to standard heart failure therapy …” “… when compared with standard therapy alone …” “… lead to lower mortality or morbidity from thromboembolism. Is this enough to be worth the increased risk of bleeding?”

From http://www.cebm.net/asking-focused-questions/


Types of Questions

Diagnostic Tests – how to select and interpret diagnostic, in order to confirm or exclude a diagnosis, based on considering their precision, accuracy, acceptability, safety, expense, etc.
Harm/Etiology – how to identify causes or risk factors for disease.
Prognosis – how to estimate patient’s likely clinical course over time and anticipate likely complications of the disorder.
Therapy – how to select treatments to offer patients that do more good than harm and that are worth the efforts and costs of using them.
From Straus SE, Richardson WS, Glasziou P, Haynes RB. Evidence-based medicine: How to practice and teach EBM. 3. ed., repr. ed. Edinburgh [u.a.]: Elsevier/Churchill Livingstone; 2008.

Levels of Evidence

There are several levels of evidence, all related to the types of research and publications.  Many evidence based resources incorporate evidence that ranges from the very highest level to the very basic level.