|
Sources of Evidence
|
Classification |
| Meta-analysis of multiple well-designed controlled studies |
1A
|
| Well-designed randomized controlled trials |
1
|
| Well-designed non-randomized controlled trial (quasi-experiments) |
2
|
| Observational studies with controls (retrospective studies, interrupted time-series studies, case-control studies, cohort studies with controls) |
3
|
| Observational studies without controls (cohort studies without controls and case series) |
4
|
|