Table 3 Quality categories and criteria for assignment
Quality categories | Criteria |
|---|---|
Category 1 | High risk of bias (quality criteria 1 is not fulfilled) |
Category 2 | Moderate risk of bias (quality criteria 1 is fulfilled) |
Category 3 | (1) Moderate risk of bias (quality criteria 1 is fulfilled) and (2) At least four of the six quality criteria listed in Table 2 are fulfilled and (3) Quality criteria 3 and 6 are fulfilled |