# Error Signal
**Domain:** Control Theory / Measurement
**Doc Type:** Concept Node
**Maturity:** Developing
**Related:** [[Feedback Channel]], [[Educational Telemetry]], [[Control Systems]], [[Russia and Prussia Kybernetiks]]
---
## Definition
A representation of the difference between a measured system state and its [[Setpoint|reference condition]].
## Kybernetiks Context
Grades, test results and performance indicators become error signals when institutions use them to trigger correction, ranking or rerouting.
## Backlinks
[[Russia and Prussia Kybernetiks]] · [[articles/Russia and Prussia Kybernetiks|Russia and Prussia Kybernetiks]]