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Dietitian Education Program

What is Evidence Based Practice?


Formulating a PICO question is the first step in the process of carrying out a focused literature review and analysis of evidence.

PICO is an acronym for the elements of the clinical question: a way of asking a clinical question that will help guide the search for evidence.


P = Patient population of interest: Identify patients by age, gender, ethnicity, disease or health problem

I = Intervention of interest (can also be issue of interest that has no comparison): Which intervention is worthwhile to use in practice? Which issue is studied (e.g. a treatment, diagnostic test, prognostic factor)?

C = Comparison of interest (you do not always have a comparison): What is the usual standard of care or current intervention used now in practice?

O = Outcome: What results do you wish to achieve or observe as a result of an intervention (e.g. change in patient behavior, physical findings, patient perception)?

modified from University of North Florida

Example of a PICO Question

"How effective is the consumption of low glycemic index foods for reducing energy intake and promoting weight loss in adults?

Population Adults
Intervention Consumption of low glycemic index foods
Comparison No comparison

Weight loss, and reduced energy intake


This scenario will help you to develop a PICO Question: 

Scenario: A 47 year old woman comes to see you. She is overweight, concerned about her overall health, and would like to lose weight quickly. She has heard a report on the radio suggesting that resistant corn or potato starch can reduce obesity. You begin to investigate any evidence to support this.

Population: overweight adults

Intervention: resistant starch

Comparison: ordinary starch

Outcome: weight loss


PICO Question: In overweight adults, how does resistant starch compared with ordinary starch effect weight loss?

modified from University of North Florida

Sample CINAHL Search

sample CINAHL database search

Sample PubMed Search

Brief Overview of Levels of Evidence

Idaho State University Libraries

Detailed Overview of Levels of Evidence

Rite Aid Information Commons

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