Definitions for

**"CONTROL CHART"****Related Terms:**Statistical process control , Statistical control, Control limits, Spc, Process capability, Statistical quality control, Histogram, Sqc, Kriging, Run chart, Stochastic process, Markov process, Confidence intervals, Confidence interval, Confidence limits, Anova, Bootstrapping, Cpk, Analysis of variance, Statistic, Confidence level, Bayesian network, Sep, Extrapolation, Estimation, Estimator, Descriptive statistics, Stochastic, Factor analysis, Variance, Variability, Deviation, Error variance, Random error, Markov chain, Normal distribution, Parametric test, Monte carlo simulation, Standard error of the mean, Calibration, Bootstrap, Stochastic model, Common cause, Linear regression, Analysis of covariance, Chi-square test, Variation, Principal component analysis, Bias

A graphical rendition of a characteristic's performance across time in relation to its natural limits and central tendency.

A graphic representation of what a process is producing. 171

a chart that displays Statistical Process Control data.

A line graph that identifies the variation occurring in a work process over time; helps distinguish between common-cause variation and special-cause variation.

A time plot that includes a centerline and upper and lower control limits. The control limits are statistically calculated from the data in the plot. These limits allow you to quickly detect specific changes in a process. A control chart also helps quantify the current capability of a process and identify when special events interrupt usual operations.

A statistical tool for problem solving that indicates control of a process within established limits.

A control chart sifts out (identifies) two types of variation in a process, common causes and special causes. See Common Causes and Special Causes.

A graph which is used to monitor the stability of a process by plotting summary statistics of samples taken sequentially over time.

(1) A graphic comparison between the process's performance and computed limits know as control lines. This statistical method is used to decide when to take action and when to leave a process alone. The charts can identify when statistically unnatural patterns occur so their cause can be investigated. Tool for monitoring process variation. (2) A plot of the process output against time or observation order. The variation observed is used to determine and plot the process average and the upper and lower control limits set at three standard deviation from the average. Observations outside the control limits and other patterns indicate the presence of special cause variation.

a chart that is used to detect and verify process variations

a data analysis analysis technique for determining if a univariate measurement process has gone out of statistical control

a graphical approach to quality control

a graphical representation of the central tendency and dispersion of a set of observations (defects)

a graph or chart with limit lines, called control lines

a particular statistical tool to distinguish when a particular process is out of command

a particular tool you can make use of to monitor a particular process

a plot of a measurements over time with statistical limits applied

a plot of statistics over time

a popular statistical tool for monitoring and improving quality

a run chart which includes statistically determined limits, calculated from the data of the process

a statistical tool used to aid in keeping the product uniform

a statistical tool used to distinguish between variation in a process resulting from common causes and variation resulting from special causes

a time plot with control limits added to show the range of values that would be typical of the process

A statistical tool used to track an important condition over time and to watch for changes in both the average value and the variation.

A graphic display of the results of a process over time and against established control limits. The dispersion of data points on the chart is used to determine whether the process is performing within prescribed limits and whether variations taking place are random or systematic.

Monitors variance in a process over time and alerts the business to unexpected variance which may cause defects.

A cumulative summary chart of results from QA tests with reference materials (e.g. reference toxicants). The results of a given QA test are compared to the control chart mean value and acceptance limits (typically 95% confidence limits, i.e. mean + 2 standard deviations) or warning limits (typically 99% confidence limits, i.e. mean + 3 standard deviations).

a graphic representation of a characteristic of a process that shows plotted values of statistical data gathered from that characteristic, a central line, and one or two statistically derived control limits. [EIA 557

A chart with upper and lower control limits on which values of some statistical measure for a series of samples or subgroups are plotted. The chart frequently shows a central line to help detect a trend of plotted values toward either control limit.

A line graph where some shtmlect of quality is plotted over time within the context of statistical control. It is a comparative tool, often used to track changes in performance from previous levels.

A chart that indicates upper and lower statistical control limits, and an average line, for samples or subgroups of a given process. If all points on the control chart are within the limits, variation may be ascribed to common causes and the process is deemed to be "in control." If points fall outside the limits, it is an indication that special causes of variation are occurring, and the process is said to be "out of control."

A tool for monitoring changes that occur within a process, by distinguishing variation that is inherent in the process (common cause) from variation that yield a change to the process (special cause). This change may be a single point or a series of points in time - each is a signal that something is different from what was previously observed and measured.

A statistical method for distinguishing between common and special cause variation exhibited by processes.

A graphic technique for identifying whether an operation or process is in or out of control and tracking the performance of that operation or process against calculated control and warning limits.

A graphic display of the results, over time, and against established control limits, of a process. The chart is used to determine if the process is in control or in need of adjustment. (PMI)

The control chart, also known as the 'Shewhart chart' or 'process-behaviour chart' is a statistical tool intended to assess the nature of variation in a process and to facilitate forecasting and management. A control chart is a more specific kind of a run chart.