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Evidence-Based Practice

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Ask a question

The first step of Evidence Based Practice is to identify your question. You may have background questions surrounding your own knowledge of the condition that you are dealing with, or you may have local patient questions that you can't look up - for example, how the patient feels.

Your foreground questions are the specific, answerable questions, such as whether one treatment is better than another. Use PICO to help you to structure your foreground question, then convert this into a search.

Searching for evidence: PICO

To find evidence upon which to base a decision for a clinical situation, phrase your scenario as an answerable question before choosing a resource to search.

PICO (Patient/ Population, Intervention/ Indicator, Comparison/ Control and Outcome) can help provide a structure for this, and guide you in developing search terms.

In P (your patient or population), how does I (your intervention or indicator) compared with C (your comparison or control) affect O (the outcome that you are looking for)?

For example, your patient is a 53 year old woman who has made several unsuccessful attempts to cease smoking. 

She heard on the radio that antidepressants may help with quitting, and thinks that this would be better for her than quitting without support. 

What evidence is there to support this?

PICO element   Definition Scenario Potential search terms
 P (patient/ population/ problem) Describe your patient, population or problem 53 year old female smoker who is trying to quit   Smoker OR smokes OR smoking
 I (intervention/ indicator) Describe your intervention or indicator Antidepressants Antidepressant* OR [specific medication]
 C (comparison/ control) What is your comparison or control? No treatment N/A
 O (outcome)   What outcome are you looking for? successful cessation of smoking Quit OR cease OR cessation


Translate PICO into a search by brainstorming for relevant search terms (include synonyms).  You don't need to search on all of the elements at once.

For example, antidepressant* AND smok* would be a sufficient search for this scenario.

Note: '*' is a truncation symbol used in keyword searching. 

Adding this to part of a keyword will broaden a search as the database searches for alternative endings for that word. 

Smok* will retrieve smoke, smokes, smoking, smoker.

If you think age and gender is relevant to your question, you can use relevant limits in databases such as Medline, CINAHL and PsycINFO to restrict your results further.  In this scenario, it isn't necessary.

Now that you know how to construct a search from a clinical question, look at Access the evidence to determine what to search.

Evidence-Based Practice step-by-step search planner

Download this document to take you through each of the stages of finding evidence for your specific clinical question.