A consultant (from Latin: consultare "to discuss") is a professional who provides professional or expert advice in a particular area such as security (electronic or physical), management, accountancy, law, human resources, marketing (and public relations), finance, engineering, science or any of many other specialized fields .
A consultant is usually an expert or a professional in a specific field and has a wide knowledge of the subject matter. The role of consultant outside the medical sphere (where the term is used specifically for a grade of doctor) can fall under one of two general categories:
The overall impact of a consultant is that clients have access to deeper levels of expertise than would be feasible for them to retain in-house, and may purchase only as much service from the outside consultant as desired.
Consultant Peter Block defines a consultant as "someone who has influence over an individual, group, or organization, but who has no direct authority to implement changes." He contrasts this with a surrogate manager who is a person who "acts on behalf of, or in place of, a manager." The key difference is that a consultant never makes decisions for the individual or group, whereas a surrogate manager does make decisions.
Accredited Associates are bound by a Code of Ethics that requires the consultant to only provide “practical advice that works” — by “Analysing as a Generalist and Solving as a Specialist” — using the skills and experience of a sub-contracted fellow Associate, thus at all times providing the client with the best available advice and support.
There is no single qualification to be a consultant other than those laid down in relation to medical & engineering personnel who have attained this level-degree in it.