Definition of feedback

term used to refer to information concerning actual performance, particularly in comparison with the plan. The feedback process is a critical part of a management control system in order to test a given system or model to see if it is performing as planned. Timely feedback enables quick corrective action when things get out of hand.

1. a rating and/or comment given to help members of an on-line community determine if the rated member is trustworthy. Auction sites such as eBay or review sites like Epinions depend on user feedback to function effectively.
2. a phenomenon that occurs when a control device uses information about the current state of the system to determine the next control action. For example, when a thermostat controls the temperature in a house, it needs to know the current temperature in the house before it decides whether to turn on the furnace. Thus, information about the temperature "feeds back" into the device that controls the temperature. The thermostat, heater, and air temperature form a feedback loop. See loop (definition 2).
3. an unwanted squeal that occurs when a microphone picks up its own output from speakers. A single vibration can then go through the system over and over, producing an endless, raucous tone.

1. audience response from which advertisers can glean information about how well the advertising message is received, the environment in which it is received, and the temperament and attitude of the consumer upon its reception.
2. in video, effect created when the camera is focused on its own monitor. This will produce a series of random patterns on the television screen.
3. in audio, sound effect created whenever a microphone is held too close to its monitor speakers. At low levels, the sending of the audio signal back on itself in this way will produce an echo effect, which is sometimes used by recording artists to add another dimension to a recording. At higher levels or when uncontrolled, feedback will produce a loud squeal or howl.