The focus of this work is on the issue of managing credibility information in reasoning systems. We first discuss a closely related idea, that of multicriteria decision making. It is shown how the concept of importance in multicriteria decision making is similar to the concept of credibility in evidential reasoning systems. A new concept of credibility qualification is introduced in both the theory of approximate reasoning and the mathematical theory of evidence. A concept of relative credibility is also introduced. This relative credibility is useful in situations where the credibility of a piece of evidence is determined by its compatibility with higher priority evidence.
