A control chart is a time-series graph of process measurements overlaid with a central line (process mean) and upper/lower control limits (typically ±3 standard deviations from the mean), used to distinguish common-cause variation from special-cause signals in a running process. The method was developed by Walter A. Shewhart at Bell Labs to enable operators to detect when a process had deviated from its stable state and required intervention. Persistence mechanism: plotted on paper charts, tracked in digital monitoring systems, and embedded in quality management software. [formal: tabula controlis | substrate: behavior | horizon: hours | explicit: yes | epoch: 0.03]
Accepted ontology entry
control-chart
A control chart is a time-series graph of process measurements overlaid with a central line (process mean) and upper/lower control limits (typically ±3 standard deviations from the mean), used to distinguish common-cause variation from spe…
Definition
Why it is in scope
A human-made graphical tool for monitoring process variation over time, plotting data points against statistically calculated control limits to detect assignable-cause variation. Built to persist through standardized SPC chart templates and statistical convention.
Names and aliases
- control-charten · CANONICAL
Relations from this entry
- cmrvhabuj015f2cei72xywgzfINSTANCE_OF →
control-chart is a specific kind of analytical diagram — plots data points against control limits to detect variation.
- cmr9uz3vv00elhcxfruyltnd4DEPENDS_ON →
Removal test: remove measurement from control-chart — it stops operating because control charts function by plotting measured data points against statistical limits. Without measurement data, there is nothing to plot and no variation to detect. This is constitutive, not merely associated.
- cmsjnvjul03d4nobpgus9ra87SERVES →
Control charts are specifically designed and maintained for condition monitoring — their purpose is to detect process shifts and equipment anomalies in real-time, feeding condition assessment workflows.
- cmrwnrieo00qrsoacvm1msqk2INSTANCE_OF →
A control chart IS a specific kind of diagram: it is a time-series plot with control limits used to monitor process stability. A competent speaker calls a control chart a type of diagram.
Relations to this entry
- cmsjscyrt03jxnobp31xwv1gi← INSTANCE_OF
An x-bar chart is a specific type of control chart designed to monitor process means. 'Is an x-bar chart a specific kind of control chart?' — yes, it applies the control chart principle specifically to subgroup averages with mean-based control limits.
Record identity
- Created
- Jul 31, 2026, 4:51 AM UTC
- Content hash
- a2314374dd433400fbac0098dc8f15a18e5eb7937f683c47dccee697b37c53da