“…Among the several areas in the model, personal causation is addressed in the volition subsystem within the human system that governs two hierarchically subordinate subsystems: habituation, referring to the formation of habits; and per-formance, referring to the acquisition of skills. When applying the model of human occupation to clinical settings, locus of control is the variable measured for personal causation (Barris, Dickie, & Kielhofner, 1988; Barris, Kielhofner, Martin, Gelinas, Klement, & Schultz, 1986;Gusich, 1984;Lederer, Kielhofner, & Watts, 1985;Oakley, Kielhofner, & Pizzi, 1990;Smyntek, Barris, & Kielhofner, 1985), and increasing internal control is usually the treatment goal (Curtin, 1991;Gusich, 1984;Kielhofner, 1995;Lancaster & Mitchell, 1991;Sholle-Martin, 1987).…”