Feedback

A feedback loop where all outputs of a process are available as causal inputs to that process

Feedback occurs when outputs of a system are routed back as inputs as part of a chain of cause-and-effect that forms a circuit or loop.[1] The system can then be said to feed back into itself. The notion of cause-and-effect has to be handled carefully when applied to feedback systems:

Simple causal reasoning about a feedback system is difficult because the first system influences the second and second system influences the first, leading to a circular argument. This makes reasoning based upon cause and effect tricky, and it is necessary to analyze the system as a whole. As provided by Webster, feedback in business is the transmission of evaluative or corrective information about an action, event, or process to the original or controlling source.[2]

— Karl Johan Åström and Richard M.Murray, Feedback Systems: An Introduction for Scientists and Engineers[3]
  1. ^ Andrew Ford (2010). "Chapter 9: Information feedback and causal loop diagrams". Modeling the Environment. Island Press. pp. 99 ff. ISBN 9781610914253. This chapter describes causal loop diagrams to portray the information feedback at work in a system. The word causal refers to cause-and-effect relationships. The wordloop refers to a closed chain of cause and effect that creates the feedback.
  2. ^ "feedback". MerriamWebster. Retrieved 1 January 2022.
  3. ^ Karl Johan Åström; Richard M. Murray (2008). "§1.1: What is feedback?". Feedback Systems: An Introduction for Scientists and Engineers. Princeton University Press. p. 1. ISBN 9781400828739. Online version found here.