Evidence Based Medicine (EBM)
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Clinical questions are usually complex, multifaceted, and arise frequently in the course of daily clinical practice. Finding answers to each question can be problematic for the health practitioner due to:
- clinical practice time pressures
- a lack of awareness of high quality resources for finding research evidence
- perceived or real lack of searching skills
- the sheer size of the clinical research literature:
- > 23 million citations in PubMed alone 
- thousands of new studies published weekly
- 75 RCTs and 11 SRs published daily .
An efficient method for tackling clinical questions is to:
- Convert the question into a manageable, answerable format using the PICOS mnemonic
- Rephrase the question simply based on its PICOS
- Develop a 'logic grid' using the core concepts of the question
- Explore synonyms for each core concept in preparation for constructing an efficient, effective search strategy.
An example of a clinical scenario that needs converting to a PICOS
Go to the PICOS tab above to see how this scenario can be converted into a well-structured question.
1. U.S. National Library of Medicine. Fact sheet: MEDLINE, PubMed, and PMC (PubMed Central): How are they different? [Internet]. Bethesda, MD: U.S. National Library of Medicine; 2002 [updated 2014 May 7; cited 2015 Apr 28]. Available from: http://www.nlm.nih.gov/pubs/factsheets/dif_med_pub.html
2. Bastian H, Glasziou P, Chalmers I. Seventy-five trials and eleven systematic reviews a day: how will we ever keep up? PLoS Med. 2010 Sep; 7(9): e1000326.
What is PICO(S)?
PICO(S) is an established EBM tool that helps you clarify a specific problem, identify a gap in your own knowledge, and then formulate a clearly focused clinical question in preparation for searching for an answer.
Step 1. Turn a clinical scenario into a PICOS
This clinical scenario can be expressed as the following PICOS.
|Patient with treatment-resistant, (non-psychotic) depression||Repetitive transcranial magnetic stimulation||No transcranial magnetic stimulation||Reduction in depression severity or remission||RCTs or systematic reviews of RCTs|
Step 2. Turn the PICOS into a well-formulated question
This PICOS above can be succinctly and clearly articulated as: In patients with treatment-resistant, non-psychotic depression, is repetitive transcranial magnetic stimulation beneficial in reducing depression severity and effecting remission?
Step 3. Create a logic grid for the question
Once you have clarified your question by creating a PICOS structure for it, transfer the significant concepts in your PICO to a Logic Grid.
The Logic Grid will help you:
- identify the concepts in your question which need to searched on for your search to have a minimum level of precision
- clarify which concepts can be left out of the search, or added later if required to improve precision
- prepare for finding appropriate and useful synonyms, acronyms, variant spellings etc. for each concept.
Now go to the Intervention (therapy) question section of this guide to see how this question is developed into a search strategy and the critical appraisal questions that need to be asked.
A further PICO example
A further Logic Grid example