Control theory, or cybernetic theory, examines self-regulating systems, both mechanistic and humanistic. The theory’s central ideas have been around for many decades (for example, Cannon, 1929), but Wiener (1948) is generally attributed with establishing control theory as a distinct body of thought. Control theory has had a major impact on a diverse number of fields, such as management, engineering, applied mathematics, economics, and health care.

According to control theory, the feedback loop is the basic unit of cybernetic control (Carver & Scheier, 1982). The feedback loop contains four elements: (1) a referent standard, (2) a sensor, (3) a comparator, and (4) an effector. Many people have used the example of a thermostat to describe how the four parts of the feedback loop work together (Klein, 1989). When a thermostat controls the temperature of a room, the referent standard is the thermostat’s set temperature, the sensor is the device that monitor’s the room’s temperature, the comparator is the mechanism that compares the room’s current temperature with the set temperature, and the effector is a device that can change the temperature of the room, such as a furnace or air condit....