Table 1 Levels of Evidence according to the Oxford Center of Evidence Based medicine (https://www.cebm.net/2009/06/oxford-centre-evidence-based-medicine-levels-evidence-march-2009/)
From: Evidence-based prediction and prevention of cardiovascular morbidity in adults treated for cancer
| Level | 1 | a | Systematic review of randomised controlled trials |
| b | Single randomised controlled trial | ||
| Level | 2 | a | Systematic review of cohort studies |
| b | Individual cohort study | ||
| c | “Outcomes” research | ||
| Level | 3 | a | Systematic review of Case-Control studies |
| b | Individual Case-Control study | ||
| Level | 4 | Case-series | |
| Level | 5 | Expert opinion |