Expert

reliable source of knowledge or skill whose judgement is accorded authority and status by the public or their peers. Experts have prolonged or intense experience, practise or education in a particular field that goes significantly beyond any general or shallow appreciation. The concept is debated within the field of epistemology under the general heading of expert knowledge.

In the field of medicine, a movement called "evidence-based medicine" ranks quantitative empirical analysis, such as double blind randomized controlled trials, above the judgements of experts (i.e. medical professionals).

The term is widely used informally, with people being described as 'experts' in order to bolster the relative value of their opinion, when no objective criteria for their 'experthood' is available. The term crank is likewise used to disparage opinions. Academic elitism arises when 'experts' become convinced that only they understand their field of study.

It is not necessary for an individual to have a professional or academic qualification for them to be accepted as an expert. In this respect, a shepherd with 50 years of experience tending flocks would be widely recognized as having complete expertise in the use and training of sheep dogs and the care of sheep.

See also: Expert system, Expert witness.