A Subject Matter Expert (SME) is a person who has extensive experience (with a minimum of 10,000 documented hours in a specialty, excluding recreational and on-site, on-call hours) and expert (court recognized) knowledge in a particular discipline.
They often conduct independent research, and sign off on internal training-related documents which they will be responsible to defend in court.
SMEs are also necessary for the development of training materials and are able to speak about the current state of a particular discipline or to cite advancement of that craft.
They are often called upon to provide expert witness opinion evidence as part of a fact finding process such as investigational bodies, courts, tribunals etc. They are frequently subject to cross examination or challeenged to defend their opinions.
The IRIA international, court recognized, subject matter experts provide the infomation upon which the Risk Management Matrix depends.