Grades of recommendation and evidence levels in support of the recommendations formulated in the Maastricht IV / Florence Consensus Report
| Grade of recommendation* | Evidence level | Type of studies | |
| A | 1 | 1a | Systematic review of randomised controlled trial (RCT) of good methodological quality and with homogeneity |
| 1b | Individual RCT with narrow CI | ||
| 1c | Individual RCT with risk of bias | ||
| B | 2 | 2a | Systematic review of cohort studies (with homogeneity) |
| 2b | Individual cohort study (including low quality RCT, eg <80% follow-up) | ||
| 2c | Non-controlled cohort studies/ecological studies | ||
| 3 | 3a | Systematic review of case–control studies (with homogeneity) | |
| 3b | Individual case–control study | ||
| C | 4 | Case series/poor quality cohort or case–control studies | |
| D | 5 | Expert opinion without explicit critical appraisal or based on physiology, bench research or ‘first principles’ | |
↵* The highest grade of recommendation does not always correspond to the highest evidence level.