| Quality: High |
|---|
| Future research unlikely to change confidence in estimate of effect; e.g. multiple well designed, well conducted clinical trails |
| Quality: Moderate |
| Further research likely to have an important impact on confidence in estimate of effect and may change the estimate e.g. limited clinical trials, inconsistency of results or study limitations |
| Quality: Low |
| Further research very likely to have a significant impact in the estimate of effect and is likely to change the estimate e.g. small number of clinical studies or cohort observations |
| Quality: Very low |
| The estimate of effect is very uncertain; e.g. case studies; consensus opinion |
Modified with permission from: Guyatt GH, et al. BMJ 2008;336:926