How useful the information that an expert provides depends on:
(1) whether the information is up to date
(2) how familiar the expert is with the nuances of a specific problem
(3) whether the expert's experience is in a population that is markedly different from the patient (for example, a hematologist's differential for a sore throat is likely to be significantly different from that of a general practitioner)
(4) how familiar the expert is with the practice standards and resources available to the practitioner
(5) if the problem matches the expert's skill set (for example, an expert clinician may not be able to interpret or apply a research paper or clinical trial)
(6) how accurate the information is, especially when it has been recalled from memory
(7) how well it answers the question posed
(8) whether the expert has any incentive for making a recommendation
(9) whether the expert has a bias for or against a diagnostic or therapeutic option