| High | High confidence in the effect estimate—the true effect lies close to the estimate of the effect |
| Moderate | Moderate confidence in the effect estimate—the true effect is likely to be close to the estimate of the effect, but may be substantially different |
| Low | Low confidence in the effect estimate—the true effect may be substantially different from the estimate of the effect |
| Very Low | Very low confidence in the effect estimate—the true effect is likely to be substantially different from the estimate of effect |