“‘Feedback can be defined as information about past behavior delivered in the present which may influence future behavior.” - Seashore, Charles N., Edith W. Seashore, and Gerald M. Weinberg. What did you say? : the art of giving and receiving feedback. Columbia, Md: Bingham House Books, 1997.
“Feedback is systems-based data useful for improvement.” - Scholtes, Peter R. The leader’s handbook : making things happen, getting things done. New York: McGraw-Hill, 1998.
“Feedback, by definition, is information that helps one reach goals by showing that the current progress is either on or off target.” - Schein, Edgar H. Helping : how to offer, give, and receive help. San Francisco, CA: Berrett-Koehler, 2009.