A measurable decline in a process output, typically referring to a sudden loss of yield, a reduction in defect counts, or a downward shift in a control chart mean. Engineers monitor drops closely because an unexpected decrease in yield signals a new special cause of variation. Conversely, a drop in defect density indicates a successful process improvement.
We saw a massive yield drop at step four after the maintenance cycle, so pull the logs and check the tool calibration.
Related terms
Yield
Fraction of units that come out good at a step or across a whole process, the headline number for any production line.
Shift
Sudden, sustained step change in a process mean, often after a maintenance event, material change or recipe edit.
Excursion
Sudden departure of yield, defect counts or a key parameter from its normal band, big enough to trigger holds and an investigation.
Special cause
Specific, identifiable source of variation that is not part of the process's normal behavior and shows up as a chart signal.
Same word, different worlds
The final fiber cable run from a distribution terminal on the street to a single customer building.
Sealants & WaterproofingA vertical strip of facade worked from top to bottom on one setup of a swing stage or bosun's chair.
Production & ManufacturingA scheduled delivery of parts, materials, or finished goods to a specific location on the floor.