High quality within a Lean production system begins with standardised work, which creates stable processes able to generate predictable output. If nonconformity from the standard procedures occurs, routines are needed to analyse, correct and prevent the nonconformity from occurring again. In that way, the nonconformity can be a trigger for continuous improvements toward more stable processes. In takted production lines, where the operator follows a standard sequence with tasks set to be completed within the takt time, a nonconformity leads to downtime in the operator?s sequence, and no value is added.