Appraising the evidence
There are two criteria: The level of evidence and utility.
The level of evidence (*1)
The level of evidence is the ability of the evidence to reliably predict cause-effect.
Evidence Level (level 1 trumps level 2; level 2 trumps level 3; etc.)
| Evidence Level | Study Type |
| 1 | Systematic review of randomized controlled trials and randomized controlled trials |
| 2 | Systematic review of cohort trials, and cohort trials |
| 3 | Systematic review of case-control trials, and case-control trials |
| 4 | Case series |
| 5 | Narrative review |
| Not Applicable | Case report, epidemiology, animal studies, in vitro studies |
Clinical utility (*2)
Clinical utility is based on:
- Validity (freedom from bias)
- Clinical importance (difference between experimental and control group)
- Clinical relevance (importance to patients one treats)
* References
- Levels of evidence and grades of recommendation. Centre for Evidence-Based Medicine, Oxford.
- Critical appraisal tools. Critical Appraisal Skills Program, Oxford.
