SPC Concepts

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Statistical Process Control Concepts

SPC is the primary analysis tool of quality improvement. It is the applied science that helps you collect, organize and interpret the wide variety of information available to your business. Whether you track revenues, billing errors, or the dimensions of manufactured components, SPC can help you measure, understand and control the variables that affect your business processes.

SPC analyzes the variation in whatever process you are measuring:

First, control charts demonstrate how consistently your process is performing, and whether you should, or should not, attempt to adjust it.
Next, the statistical process control chart compares the process performance to your customers' requirements, providing a process capability index as an ongoing, accurate direction for quality improvement.
Finally, control charts and its resulting process capability index quickly evaluate the results of quality initiatives designed to improve process consistency.

As part of an ongoing cycle of continuous process improvement, SPC can help you fine-tune your processes to the virtually error free Six Sigma level.

Statistical Process Control is easy to do. Although it involves complex mathematics, computers are ideally suited to the task. They easily collect, organize and store information, calculate answers, and present results in easy to understand graphs, called control charts. Computers accept information typed in manually, read from scanners or manufacturing machines, or imported from other computer databases. The resulting control charts can be examined in greater detail, incorporated into reports, or sent across the Internet. A computer collecting information in real time can even detect very subtle changes in a process, and even warn you in time to prevent process errors before they occur.

SPC can help you understand and reduce the variation in any business process. Greater consistency in fulfilling your customer's requirements leads to greater customer satisfaction. Reduced variation in your internal processes leads to less time and money spent on rework and waste. Both directly yield greater profitability and security for your business. SPC is one of the essential tools necessary to maintain an advantage in today's competitive marketplace.

Understanding the following concepts is essential to interpretation of Statistical Process Control Charts:

(SPC) Statistical Process Control chart properties

Rational Subgroups

Defining Control Limits

SPC Training Materials for self-study or instructors

For information on When To Use, How To Interpret, or Calculations for each chart:

Attributes Charts: P charts, U charts, Np charts, C charts

Pareto Charts

X-Bar / Range Charts

X-Bar / Sigma Charts

Individual-X Charts (X-Charts)

Histograms / Process Capability Analysis