Hierarchies of Evidence-based medicine are explained in the following figure.
The types of study include:
- Case reports and case series
- Cross-sectional studies
- Case-control studies
- Cohort studies
- Randomized control trials (RCTs)
- Systemic review and metaanalysis
Level of evidence (Hierarchies of Evidence-based medicine)
| Level | Studies |
|---|---|
| 1a | Systemic review with homogeneity (SRwH) of RCTs |
| 1b | Individual RCT with a narrow confidence interval |
| 1c | All or none |
| 2a | SRwH of cohort studies |
| 2b | Individual cohort study |
| 2c | Outcome research: ecological studies |
| 3a | SRwH of case-control studies |
| 3b | Individual case-cohort studies |
| 4 | Case series (Poor quality cohort and case-control) |
| 5 | Expert opinion with/ without an explicit critical appraisal, or based on physiological, bench research, or first principles |
See also: Recent advances in Orthopaedics
