Feedback is a process in which information about the past or the present influences the same phenomenon in the present or future. As part of a chain of cause-and-effect that forms a circuit or loop, the event is said to "feed back" into itself.
Ramaprasad (1983) defines feedback generally as "information about
the gap between the actual level and the reference level of a system
parameter which is used to alter the gap in some way", emphasising that the information by itself is not feedback unless translated into action.