Hierarchy of Evidence (Duke University Medical Center Library & Archives, 2024)
The type of question will often dictate the best study design to address the question. In the absence of the best study design, move down the hierarchy of evidence:
| Type of Question | Type of Study Design |
|---|---|
| Therapy | Randomized Controlled Trial (RCT) > Cohort study > Case control study > Case series |
| Diagnosis | Prospective, blind comparison to a gold standard or Cross-sectional |
| Aetiology/Harm | Cohort study > Case control study > Case series |
| Prognosis | Cohort study > Case control study > Case series |
| Prevention | Randomized Controlled Tria (RCT) > Cohort Study > Case control > Case series |
| Clinical exam | Prospective, blind comparison to a gold standard |
| Cost | Economic analysis |