A “challenge” is a task the accomplishment of which requires a special achievement. A “challenge” exists when someone is entrusted with doing something whose completion imposes requirements that go beyond the usual extent.

Three elements are constitutive of the concept of “challenge”: first, the existence of a task in the sense of an event to take specific actions in order to achieve a well-defined goal. Secondly, a level of demands imposed on the actors for the fulfilment of the task that exceeds the usual. And thirdly, the need for a special effort on the part of the actors, which requires skills and abilities far beyond any usual tasks.