Triz Principle 23 # Feedback

Feedback is taking or sensing the output of a system and using this to change events which happen before, such as a thermostat being used to control temperature. You can also reverse feedback, perhaps to exaggerate or accelerate change or to cancel out an undesirable effect.

When we send a simple email through Internet, there is no way to know whether the person did receive it or not. This problem can be solved by using “request receipt” option or “request acknowledgement option”.

 A. Introduce feedback (referring back, cross-checking) to improve a process or action.

  • Automatic volume control in audio circuits
  • Signal from gyrocompass is used to control simple aircraft autopilots.
  • Statistical Process Control (SPC) — Measurements are used to decide when to modify a process. (Not all feedback systems are automated!)
  • Budgets –Measurements are used to decide when to modify a process.

 B. If feedback is already used, change its magnitude or influence.

  • Change sensitivity of an autopilot when within 5 miles of an airport.
  • Change sensitivity of a thermostat when cooling vs. heating, since it uses energy less efficiently when cooling.
  • Change a management measure from budget variance to customer satisfaction.


1. Use of patients medical record and listening to their feedback to previous prescription can greatly influence effectiveness of attending physician.

2. Using customer feedback for process improvement.


 Giving consistent feedback to child or husband is most successfulway by housewives to change their behaviour.

Boss and coach also give feedback for skill development.