Table 1

Criteria for assigning level of evidence to a recommendation

Level of evidence


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

- Anecdotal evidence or clinical experience

Adapted from: Lau DC et al. 2007 [36]

Tremblay et al. International Journal of Behavioral Nutrition and Physical Activity 2011 8:98   doi:10.1186/1479-5868-8-98

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