Table 1 Study type according to evidence level
| Grade | Study type |
|---|---|
| 1 (high) | Systematic literature review targeting RCTs (systematic review with/without meta-analysis) |
| 2 | Randomized controlled trial, systematic literature review targeting category 3 |
| 3 | Quasi-RCT, cohort study, case-control study, observational/analytic study |
| 4 (low) | Cross-sectional study, case series, before/after study, case report, non-analytic study |