CB Foundation Behaviour of such intensity, frequency or duration that the physical safety of the person or others is likely to be placed in serious jeopardy, or behaviour which is likely to seriously limit or deny access to or use of ordinary community facilities, or impair a child's personal growth, development and family life.

Challenging behaviour is defined as "culturally abnormal behaviour(s) of such intensity, frequency or duration that the physical safety of the person or others is placed in serious jeopardy, or behaviour which is likely to seriously limit or deny access to the use of ordinary community facilities" Emerson, E. 1995. Challenging behaviour: analysis and intervention with people with learning difficulties. Cambridge: Cambridge University Press.