| Ia | Evidence obtained from meta-analysis or systematic review of randomized controlled trials. |
| Ib | Evidence obtained from at least one randomized controlled trial. |
| IIa | Evidence obtained from at least one well-designed controlled study without randomization. |
| IIb | Evidence obtained from at least one other type of well-designed quasi-experimental study without randomization. |
| III | Evidence obtained from well-designed non-experimental descriptive studies, such as comparative studies, correlation studies and case studies. |
| IV | Evidence obtained from expert committee reports or opinions and/or clinical experiences of respected authorities. |
Women and Children
Promoting Asthma Control in Children
Practice Recommendations