Sr

Sr. Callista Roy

Roy proposes that a person's adaptation level is a constantly changing point, made up of focal, contextual, and residual stimuli, which represent the person's own standard of the range of stimuli to which one can respond with ordinary adaptive responses.

She describes a system as a set of parts connected to function as a whole for some purpose, and it does so by the interdependence of its parts. In addition to having wholeness and related parts, systems also have inputs, outputs, and control and feedback processes (Tomey & Alligood, 1998).