| LEVEL Ia | Evidence obtained from meta-analysisG or systematic reviews of randomized controlled trials, and/or synthesis of multiple studies primarily of quantitative research. |
| LEVEL Ib | Evidence obtained from at least one randomized controlled trial. |
| LEVEL IIa | Evidence obtained from at least one well-designed controlled studyG without randomization. |
| LEVEL IIb | Evidence obtained from at least one other type of well-designed quasi-experimental study, without randomization. |
| LEVEL III | Synthesis of multiple studies primarily of qualitative research. |
| LEVEL IV | Evidence obtained from well-designed non-experimental observational studies, such as analytical studies or descriptive studies, and/or qualitative studies. |
| LEVEL V | Evidence obtained from expert opinion or committee reports, and/or clinical experiences of respected authorities. |
Chronic Disease
Adult Asthma Care Guidelines for Nurses: Promoting Control of Asthma
Practice Recommendations