‘Communication is an exchange of facts, ideas, opinions or emotions by two or more persons.” The process of communication is incomplete until the sender receives the feedback. If the feedback is in tune with the message, communication is said to be effective. 

Feedback is the key element in communication as it is the only way of judging the effectiveness of the message. Feedback indicates the knowledge about the outcome of communication. It begins when the receiver responds to the message and ends when the response reaches the sender. Feedback enables the sender to know whether his message has been properly understood or not. 

Feedback varies from one situation to another. In face-to-face communication there is immediate feedback. The sender can judge the effect of his message from the face of the receiver. While, in case of written messages, the feedback is not available immediately. The writer cannot see the facial expressions of the receiver. Feedback does not become available automatically in all situations. Feedback may also be collected through grapevine or oral communication.