Clinical Questions, PICO, & Study Designs – Evidence-Based …

Two additional important elements of the well-built clinical question to consider are the type of foreground question and the type of study (methodology). This information can be helpful in focusing the question and determining the most appropriate type of evidence.

Foreground questions can be further divided into questions that relate to therapy, diagnosis, prognosis, etiology/harm

Therapy: Questions of treatment in order to achieve some outcome. May include drugs, surgical intervention, change in diet, counseling, etc. Diagnosis: Questions of identification of a disorder in a patient presenting with specific symptoms. Prognosis: Questions of progression of a disease or likelihood of a disease occurring. Etiology/Harm: Questions of negative impact from an intervention or other exposure.

Knowing the type of foreground question can help you select the best study design to answer your question. You always want to look for the study design that will yield the highest level of evidence. Consult the pyramid (click the image to enlarge it) and the definitions below.

To see more info on the relationship between study design and question type, check out Chapter Three "What is the Question? Clarifying Your Question" from the Users' Guide to the Medical Literature.

Definitions of Study Types (From the British Medical Journals Clinical Evidence Glossary http://clinicalevidence.bmj.com/ceweb/resources/glossary.jsp)

Meta-analysis: A statistical technique that summarizes the results of several studies in a single weighted estimate, in which more weight is given to results of studies with more events and sometimes to studies of higher quality.

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Clinical Questions, PICO, & Study Designs - Evidence-Based ...