Any process comes with a certain amount of variability but identifying whether the process has gone out of control or not requires the right tools. In project management, it is important to use tools. The seven basic quality tools are very important and one of them are control charts. A control chart is a tool that is used to determine the predictability, behavior and stability of the process over time.
The control chart tool is part of the quality control management and it is a graphic display of the data against established control limits to reflect both the maximum and minimum values. It has a centerline that helps determine the trend of the plotted values toward the control limits. The control chart has three components which include the center line, specification limit and control limits. Calculating the components can help determine whether values have exceeded the specification limits or not. A process is considered as out of control if the calculated data exceeds the control limit or if seven consecutive points are way below or above the mean. Values that exceed the specification limits may incur penalties.
The control chart is necessary for project management as it provides the project manager as well as the stakeholders the ability to determine points which they can implement corrective actions to prevent further problems. This particular tool is developed for processes that are repetitive by nature and that the expectations are set to perform around the variable X wherein the process involves doing the same thing and produces the same expected results.
Aside from being used to track the repetitive activities in processes, it can also be used to monitor the volume, cost, schedule variances, frequency of scope changes as well as other management results to determine whether the project management processes are still within the acceptable range or control.
This term is defined in the 5th edition of the PMBOK.