|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
|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.
Adult Asthma Care Guidelines for Nurses: Promoting Control of Asthma