Level of evidence
Synonym(s)
DefinitionThis section has been translated automatically.
General informationThis section has been translated automatically.
The level of evidence is categorized according to four levels. The evidence statements must be included as a priority in the corresponding therapeutic considerations, but are only one - albeit significant - instrument in therapeutic decision-making.
The limitation of evidence-based classifications becomes apparent, among other things, in situations in which no or only insufficient clinical studies are available or are not feasible for methodological reasons or because ethical concerns stand in the way of implementation.
A "NON-evidence", non-evidence, concerns in dermatology with >2400 diseases the vast majority of all known entities. For example, for all genodermatoses, for all primary and secondary immunodeficiencies, for most of the diseases classified as rare (<5/10,000/s.u.Orphan Diseases) evidence for any therapeutic procedure is missing. This relativizes their value for everyday use.
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Evidence level and type
Level of evidence |
Type of evidence |
Ia |
at least one systematic review based on methodologically high-quality, controlled, randomised clinical trials (RCTs) |
Ib |
at least one sufficiently large, methodologically high-quality RCT |
IIa |
at least one high-quality study without randomisation |
IIb |
at least one high-quality study of a different type or a quasi-experimental study |
III |
more than a methodologically high-quality non-experimental study |
IV |
opinions and beliefs of respected authorities (from clinical experience); expert commissions; descriptive studies |
Degree of recommendation |
Definition |
A |
findings based on validated Level 1 studies |
B |
findings based on validated Level 2 studies or Level 3 studies or on extrapolations from Level 1 studies |
C |
findings based on level 4 studies or on extrapolations from level 2 or 3 studies |
D |
findings based on Level IV or inconclusive or unsubstantiated studies of all levels of evidence |