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Evidence-Based Clinical Practice

A guide to EBCP and resources.

Formulate a Search Strategy

The PICO format for clinical questions, detailed on the Step 1: Ask page of this guide, helps to guide your search for evidence in two ways:

  1. By simplifying the question, it helps to clarify the type of clinical question you are asking (e.g., therapy, etiology). The type of clinical question indicates which study designs are best suited to answer your question.
  2. It allows you to identify the most important elements of your clinical question. These concepts are used to create search terminology.

Search Terms

We can translate the natural language from our PICO components into keywords and subject headings (e.g., MeSH). You don't necessarily need to create search terms for every component.

Take this PICO question for example: In patients on oral antibiotics, do probiotics prevent diarrhea?

 

Population

 Intervention Comparison Outcome
PICO Elements In patients on oral antibiotics do probiotics none prevent diarrhea?
Pubmed Search Terms antibiotics OR "anti-bacterial agents"[Mesh] OR "anti-bacterial agents"[Pharmacological Action] probiotics OR "Probiotics"[Mesh]   diarrhea OR "Diarrhea"[mesh]
Full Search Strategy (antibiotics OR "anti-bacterial agents"[Mesh] OR "anti-bacterial agents"[Pharmacological Action]) AND (probiotics OR "Probiotics"[Mesh]) AND (diarrhea OR "Diarrhea"[mesh])

Study Design

Different types of clinical questions are best answered by different types of research studies. 

You might not always find the highest level of evidence (i.e., RCT, systematic review/meta-analysis) to answer your question. When this happens, work your way down to the next highest level of evidence.

This table suggests study designs best suited to answer different types of clinical question.
Clinical Question Suggested Research Designs

All Clinical Questions

Systematic review, meta-analysis
Therapy

Randomized controlled trial (RCT), meta-analysis
Also: cohort study, case-control study, case series
Etiology

Randomized controlled trial (RCT), meta-analysis, cohort study
Also: case-control study, case series
Diagnosis

Randomized controlled trial (RCT)
Also: cohort study
Prevention

Randomized controlled trial (RCT), meta-analysis
Also: prospective study, cohort study, case-control study, case series
Prognosis

Cohort study
Also: case control study, case series
Quality Improvement Randomized controlled trials (RCT)
Also: qualitative study
Cost

Economic evaluation