Two additional elements of the well-built clinical question are the type of question and the type of study. This information can be helpful in focusing the question and determining the most appropriate type of evidence or study.
The type of question is important and can help lead you to the best study design:
| Most common type of questions: | Type of study: |
|---|---|
| Diagnosis how to select and interpret diagnostic tests |
prospective, blind comparison to a gold standard or cross-sectional |
| Therapy how to select treatments that do more good than harm and that are worth the efforts and costs of using them |
randomized controlled trial > cohort study |
| Prognosis how to estimate the patient’s likely clinical course over time (based on factors other than the intervention) and anticipate likely complications of disease) |
cohort study > case control > case series |
| Harm/Etiology how to identify causes for disease (including iatrogenic forms) |
cohort > case control > case series |
