Those characteristics, skills and knowledges of an expert which distinguish experts from novices and less experienced people
Since expertise in the nuclear industry can be either in performing special tasks which require special skills (e.g. welding), or being outstanding competent in much broader subjects, like reactor physics, the assessment of the different expertise requires different methods.
In certain - mostly scientific or engineering - areas there are relatively good means to quantify an expert's quality:
- the existence and grade of his/her qualifications (diploma, certificates etc.),
- the number of publications in the special field, their impact factors, citations and other scientometric parameters,
- the number and quality of the technical reports where he/she was the author or the leader.
- the number of his/her patents,
- the number of the grants where he/she was the leader of, or just participated in, etc.
In many other fields assessing the expertise of a person to be hired is more difficult, and needs different - sometimes ad hoc - methods. For example solving a test problem can be requested from the applicant, or designing or preparing a test object, or he/she should perform a test action (e.g. welding) for testing some special skills.
At certain positions in the nuclear industry the expertise of a person is checked not only when entering in the organization, but also again and again in regular intervals. An example for this is the performance test of the reactor operators on simulators, which is necessary to prolong their license.