Evidence Based Medicine: Formulating Questions
Converting the patient dilemma into a well-built clinical question
When a clinical question arises from the care of a patient, the first step in the EBM process is to formulate a question. A well formulated question facilitates a literature search strategy that results in literature relevant to the patient question.
Using PICO to formulate a clinical question
One template for formulating a clinical question is the PICO model developed by W. Richardson. According to Richardson (1995) the question should be phrased to facilitate searching for a precise answer. To achieve these aims it has been proposed that the question must be complete and composed of all 4 parts of its anatomy:
|P||the patient or problem being addressed||How would you describe a group of patients similar to yours? May include the primary problem, disease, or co-existing conditions, gender, age or race.|
|I||the intervention or exposure being considered||What is the intervention or treatment being considered for this patient or problem? This may be a treatment, therapy, or product/protocol recommendation.|
|C||the comparison intervention or exposure, if relevant||What is the main alternative to compare with the intervention? Are you trying to decide between two drugs, a drug and no medication or placebo, or two diagnostic tests? Your clinical question may not always have a specific comparison.|
|O||the clinical outcome
|What can you hope to accomplish, measure, improve or affect? What are you trying to do for the patient? Relieve or eliminate the symptoms? Reduce the number of adverse events? Improve function or test scores?|
|Additional questions to ask||
Additional questions to ask concerning study designs
In addition to PICO, there are two additional questions that are helpful: 1) What type of question are you asking? Determining this will help you answer 2) What type of study do you want to find? Use the chart below to guide you.
|Type of question||Suggested study type|
|Diagnosis– how to select and interpret diagnostic tests||
|Therapy– how to select treatments that do more good than harm||
|Prognosis– how to estimate the patient’s likely clinical course over time and anticipate complications||
|Etiology or Harm– concerning causes or contributing factors of disease
|Prevention– how to prevent disease||
|Quality Improvement– how can the quality be improved based on client health and professional experience
- Tools from the National Library of Medicine (NLM) (downloadable as an app for iOS or Android)
- PICO Search- Enter PICO information on a form and automatically retrieve relevant literature from MEDLINE/PubMed.
- askMEDLINE– free-text, natural language (English only) query for MEDLINE/PubMed