Table 10 The levels and grade of evidence scaling criteria applied to the articles.
From: A systematic review of the evidence for Canada's Physical Activity Guidelines for Adults
Level of Evidence | Criteria |
|---|---|
Level 1 |    Randomized control trials without important limitations |
Level 2 |    • Randomized control trials with important limitations |
|  |    • Observational studies (non-randomized clinical trials or cohort studies) with overwhelming evidence |
Level 3 | Other observational studies (prospective cohort studies, case-control studies, case series) |
Level 4 | Inadequate or no data in population of interest |
| Â | Anecdotal evidence or clinical experience |
Grade of Evidence | Criteria |
Grade A | Strong recommendation (action can apply to most individuals in most circumstances) |
|  |    • Benefits clearly outweigh risks (or vice-versa) |
|  |    • Evidence is at Level 1, 2, or 3 |
Grade B | Weak recommendation (action may differ depending on individual's characteristics or other circumstances) |
|  |    • Unclear if benefits outweigh risks |
|  |    • Evidence is at Level 1, 2, or 3 |
Grade C | Consensus recommendation (alternative actions may be equally reasonable) |
|  |    • Unclear if benefits outweigh risks |
|  |    • Evidence is at Level 3 or 4 |