Although several factors may account for children's differential ability to function and to adjust to persistent chronic pain, the child's sense of self-competence has been identified as a key variable in recent literature. Claar and colleagues, for example, found that in adolescents and young adults with irritable bowel syndrome, the relationship between pain and functional disability was moderated by the individual's sense of academic, social, and athletic competence. The concept of self-competence (a general sense of mastery) overlaps with that of self-efficacy (a task-specific sense of mastery), developed by Albert Bandura in the late 1970s and early 1980s 18. The concept of self-efficacy suggests an explanation for the relationship between coping skills, perceived ability to cope, and reduction in physical and psychological disability. Bandura argued that a sense of self-efficacy enables the individual to persist even with a task of great difficulty until it is mastered, to reject negative thoughts and to "bring cognitive or cerebral productions into being" that will assist in achieving the goal.