Get Statistical Process Control Charts For Measuring

The control chart is a graph used to study how a process changes over time. Data are plotted in time order. A control chart always has a central line for the average, an upper line for the upper control limit, and a lower line for the lower control limit. These lines are determined from historical data.

SPC is a good technique to use when implementing change as it enables you to understand whether changes you are making are resulting in improvement — a key component of the Model for Improvement widely used within the NHS. SPC is widely used in the NHS to understand whether change results in improvement.

Statistical Measurement Control (SMC) is a method of performing a statistical analysis of several measurements to determine the quality of the measurements and/or sample, before an average value is calculated.

Rule of Seven Tests The tests state that an out of control situation is present if one of the following conditions is true: 1) Seven points in a row above the average, 2) Seven points in a row below the average, 3) Seven points in a row trending up, or 4) Seven points in a row trending down.

Step 4: Plot Data Points and Identify Out-Of-Control Data Points RuleRule NamePattern 5 Trend 7 consecutive points trending up or trending down 6 Mixture 8 consecutive points with no points in Zone C 7 Stratification 15 consecutive points in Zone C 8 Over-control 14 consecutive points alternating up and down4 more rows

The 8 Control Chart Rules RuleRule NamePattern 1 Beyond Limits One or more points beyond the control limits 2 Zone A 2 out of 3 consecutive points in Zone A or beyond 3 Zone B 4 out of 5 consecutive points in Zone B or beyond 4 Zone C 7 or more consecutive points on one side of the average (in Zone C or beyond)4 more rows

Control chart (also called a Shewhart chart) Named after Walter A. Shewhart, this quality improvement tool can help quality assurance professionals determine whether or not a process is stable and predictable, making it easy for you to identify factors that might lead to variations or defects.

It is used in conjunction with Control Charts. The Rule of Seven as applied in Quality Management says that “A run of seven or more consecutive points in a control chart, either above the mean, or below the mean, or continuously increasing or decreasing, may indicate the process may be out-of-control”.