Feedback is what 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. Feedback may also refer to:

Engineering

* Feedback control loop, a closed-loop controller * Audio feedback, the "howl" sometimes heard in microphone or guitar amplification systems * Video feedback, the optical equivalent of audio feedback, caused when a camera films the image it is producing * Positive feedback, a feedback system that responds to perturbation in the same direction as the perturbation * Negative feedback, a method of attenuation to restore equilibrium * Negative-feedback amplifier, an amplifier designed to stabilize a system and improve performance

Human behaviour

* Corrective feedback, by a parent or teacher to guide a child's learning process * Delayed Auditory Feedback, a method of combating stuttering * Employee performance appraisal, particularly methods such as 360-degree feedback

Science

* Biofeedback * Climate change feedback, for positive and negative feedbacks associated with climate change * Reinforcement learning from human feedback, a machine learning technique that uses human feedback to directly optimize a model

Mathematics

* Feedback arc set, in graph theory, a method of eliminating directed graphs * Feedback vertex set, in computational complexity theory, the feedback vertex set problem is a graph-theoretical NP-complete problem

Comics

* Feedback (Marvel Comics), a Marvel Comics superhero * Feedback (Dark Horse Comics), the winner of ''Who Wants to be a Superhero?'' and a Dark Horse Comics superhero

Music

*Feedback (Janet Jackson song), "Feedback" (Janet Jackson song), 2008 *Feedback (Kanye West song), "Feedback" (Kanye West song), 2016 *''Feedback'', a 1944 album by Les Paul *Feedback (Spirit album), ''Feedback'' (Spirit album), 1972 *Feedback (EP), ''Feedback'' (EP), a 2004 EP by Rush *Feedback (Jurassic 5 album), ''Feedback'' (Jurassic 5 album), 2006 *"Feedback", a song by Covenant from their 1996 album ''Sequencer (Covenant album), Sequencer'' *Feedback (Derek Webb album), ''Feedback'' (Derek Webb album), 2010 *Feedback (band), a Bangladeshi rock band

Other

* ''Feedback'', a video podcast produced by G4 (American TV channel), G4 *Feedback (radio series), ''Feedback'' (radio series), a BBC Radio Four programme in the UK *Feedback, a character in ''Ben 10: Omniverse'' * Feedback, a design principle in User interface design * Feedback loop (email) * Causal loop in the context of time travel or the causal structure of spacetime, that is a sequence of events (actions, information, objects, people) {{disambiguation