Referral rating

A relatively simple coding system is used to evaluate the strength of a recommendation in terms of EMB, both the quality of the evidence on which the recommendation is based and the strength (authoritativeness) of the recommendation itself.

Assessing the quality of evidence
The level of quality of evidence/evidence (level of evidence) corresponds to how strong the scientific evidence is for the relevant findings. The scaling is as follows:


 * IA: Evidence from meta -analyses of randomized experimental trials.


 * IB: The evidence is at least one randomized experimental study.


 * IIA: Evidence from at least one experimental study without randomization.


 * IIB: The evidence is from at least one quasi-experimental study of a type other than the studies listed above.


 * III: The evidence is the results of descriptive studies without conducting an experiment, i.e. comparative studies, correlational studies or case-control studies.


 * IV: The evidence is the opinions or clinical experience of experts and authorities.

Rating the strength of recommendation
The strength (authoritativeness) of the recommendation depends primarily on the strength of the evidence on which the recommendation is based, then on how closely the evidence is related to the claim and how much the results had to be extrapolated. The grades of recommendations are as follows:


 * A: The recommendation is based directly on level I evidence.


 * B: The recommendation is based directly on level II evidence or extrapolation of a recommendation with level I evidence.


 * C: The recommendation is based directly on level III evidence or on extrapolation of a recommendation with level I or II evidence.


 * D: The recommendation is based directly on level IV evidence or on extrapolation of a recommendation with level I, II, or III evidence.

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